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General EBSD Bibliography - Search By Letter H


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216 records found


1.    Ha, C. S. and Y. B. Park (2005). Development of Growth Texture in Nanocrystalline Fe-Ni Alloys. Textures of Materials - ICOTOM 14, Leuven, Belgium, Trans Tech Publications.

In electroformed pure Ni and Fe-Ni alloys with nanometer-sized crystallites, grain growth that takes place during annealing results in a common texture change. With regard to the macrotextures, the as-deposited textures were of fibre-type characterized by strong <100>//ND and weak <111>//ND components, and the texture development due to grain growth was defined by strong <111> //ND fibre texture with the minor <100>//ND components. It was clarified by means of the microtexture analysis that abnormal growth of the <111>//ND grains occurs in the early stages of grain growth. The possible effects of the abnormal grain growth on the texture evolution have been discussed in terms of the orientation dependence of energy density.




2.    Ha, X. H., S.-W. Jang, et al. (2002). Texture Evolution in Weld Regions of SUS-304 Stainless Steel and TRIP Steel. ICOTOM 13, Seoul, Korea, Trans Tech Publications Inc.

Electron back-scattered diffraction (EBSD) analysis has been conducted on the bead-on-plate GMAW welding of stainless steel SUS-304 and TRIP steel. The grain size, texture evolution, misorientation distributions and CSL grain boundary of weld metal (WM), HAZ and base metal (BM) have been observed at various welding conditions. With increasing heat input, the grain size in all cases increased at weld metal. With increasing heat input, no significant textural change was observed, but the characteristics of misorientation distributions and the CSL grain boundary decreased.




3.    Haberjahn, M., P. Klimanek, et al. (2002). "Substructure development in cold rolled copper single crystals." Materials Science and Engineering A 324: 196-199.

Copper single crystals oriented for multislip conditions were cold rolled up to 90% reduction in thickness in order to investigate the substructure development. Both the development of the total dislocation density and the excess dislocation density connected to the disorientation were estimated by high resolution X-ray diffractometry and additionally the disorientation development by taking electron backscattering patterns (EBSP).




4.    Habiby, F. and F. J. Humphreys (1994). "The Effect of Particle Simulated Nucleation on the Recrystallization Texture of an Al-Si Alloy." Scripta Metallurgica et Materialia 30(6): 787-790.




5.    Hagstrom, J. (2005). Comparative Study of Gallium Enhanced Microscopy and EBSD for Revealing Grain Boundaries and Dislocation Subgrain Boundaries in Aluminium Alloys. 9th International Conference on Aluminium Alloys, Brisbane, Australia, Institute of Metals and Materials Australasia Ltd.

A new technique, gallium enhanced microscopy (GEM) for studying grain boundaries and dislocation subgrain boundaries in aluminium alloys was presented recently. By adding small amounts of gallium to aluminium alloys, increased visibility of grain boundaries and subgrain boundaries is achieved in the SEM. Recent GEM results show that boundaries with misorientations less than 1 deg can be detected due to the presence of gallium concentrated at them. The present paper describes briefly how the GEM method is applied and compares results obtained with this technique to characterisation using EBSD Several comparative studies of a cold rolled AA3103 alloy annealed to different conditions were performed. The results show that GEM is a very reliable tool for the characterisation of grain boundaries as well as subgrain boundaries in aluminium alloys.




6.    Hagstrom, J., O. V. Mishin, et al. (2003). "Gallium enhanced microscopy for revealing grain boundaries and dislocation subboundaries in aluminium alloys." Scripta Materialia 49(10): 1035-1040.

A new technique for studying grains and substructures in aluminium is presented. Using gallium in the SEM for increased visibility of grain boundaries and subgrain boundaries in Al-alloys has proved to be very effective. This technique is compared to characterization using EBSD and TEM and showed to be able to detect dislocation boundaries with misorientations below 1 deg.




7.    Halfpenny, A., D. J. Prior, et al. (2004). Using Electron Backscatter Diffraction (EBSD) to Measure Misorientation between ‘Parent’ and ‘Daughter’ Grains. Implications for Recrystallisation and Nucleation. Second Joint International Conference on Recrystallization and Grain Growth, ReX & GG2, SF2M, Annecy, France, Trans Tech Publications Ltd.

Electron backscatter diffraction (EBSD) is an extremely valuable tool, as it measures full crystallographic orientation information. This technique has been used to measure the statistics of misorientation between original `parent' grains and recrystallised `daughter' grains in a mylonitic quartzite. The angle of misorientation has implications on the controlling recrystallisation mechanism. The sample is a natural mylonitic quartzite collected form the stack of Glencoul, NW Scotland. The sample exhibits a common partially recrystallised microstructure. The data shows the average misorientations between the `parent' and `daughter' grains are 30 degrees, this value seems too high for only subgrain rotation recrystallisation to be taking place. Moreover there is no gradation in the boundary misorientation from the internal substructure of the `parent' grain to the `daughter' grains. The internal substructure size of the `parent' grain is bigger than the size of the `daughter' grains. For subgrain rotation recrystallisation you may expect to see a core and mantle structure and for the `daughter' grains to be of similar size to the internal substructure of the `parent' grain. Another mechanism has either controlled the recrystallisation altogether or has become active after subgrain rotation had taken place and modified the microstructure.




8.    Hall, M. G. and H. I. Aaronson (1994). "Formation of Invariant Plane-Strain and Tent-Shaped Surface Reliefs by the Diffusional Ledge Mechanism." Metallurgical and Materials Transactions A 25(9): 1923-1931.




9.    Hamedi, L. H., M. Guilloux-Viry, et al. (1998). "On the epitaxial growth of PZT films by pulsed laser deposition." Masson. Annales de Chimie-Science des Materiaux 23(1-2): 377-80.

Epitaxial Pb(ZrxTi1-x)O3 (PZT) thin films have been grown by pulsed laser deposition and structurally characterized using theta -2 theta and phi -scan X-ray diffraction, RHEED and ECP. Epitaxial relations with (100)SrTiO3 substrates have been demonstrated. The refractive indexes, measured by ellipsometry, are reported in relation with the film stoichiometry. Heteroepitaxial growth of PZT/YBCO and YBCO/PZT bilayers (YBCO=YBa2Cu3O7) has been achieved. (8 References).




10.    Hamilton, N. E. and M. Ferry (2004). "Grain Growth in a Nanocrystalline Al-Sc Alloy." Materials Transactions 45(7): 2264-2271.

A sub-micron grained microstructure in an Al-0.2 mass% Sc alloy was produced by high strain deformation using Equal Channel Angular Pressing (ECAP). The alloy was solution treated prior to deformation, deformed by ECAP then aged at low temperature to produce a sub-micron grained microstructure with a large fraction of high angle grain boundaries (HAGB) decorated with fine Al3Sc particles. General grain stability and particle/grain boundary interactions were studied using scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), focussed ion beam (FIB) microscopy and transmission electron microscopy (TEM). The fine-grained microstructure was found to he highly stable during annealing at temperatures up to 500 deg C due to Zener pinning from stable Al3Sc particles. The volume fraction, f, and average radius, r, of particles and their rate of coarsening were found to have a strong influence on grain growth. It was found that the limiting grain size, R.UL in the Al-Sc alloy may reasonably be predicted by the relation: R, = 0.l7r//'. This relation is known to be applicable for coarse-grained alloys (>1 pm) and indicates its validity for predicting the limiting grain size in sub-micron, particle-containing alloys.




11.    Hamilton, N., N. Burhan, et al. (2004). Grain growth inhibition in a nanocrystalline Al-Sc alloy. Ultrafine Grained Materials 3 Symposium, Charlotte, North Carolina, USA, TMS.

An ultrafine-grained microstructure in an Al-0.2 wt.% Sc alloy was produced by high strain deformation using Equal Channel Angular Pressing (ECAP). The alloy was solution treated prior to deformation, deformed by ECAP then aged at low temperature to produce a sub-micron grained microstructure with a high fraction of high angle grain boundaries (HAGB) decorated with nanosized Al3Sc particles. General grain stability and particle/grain boundary interactions were studied using scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), and transmission electron microscopy (TEM). The fine-grained microstructure was found to be highly stable during annealing at 450 degrees C due to Zener pinning from stable Al3Sc particles. The volume fraction and size of fine particles and their rate of coarsening were found to have a strong influence on grain growth. The grain stability in this alloy system was compared with a recent model of grain coarsening in particle-containing materials.




12.    Hammond, C., A. Nichells, et al. (1987). "Photoemission Electron-Microscopy of Superplastic Deformation Processes." Metallography 20(2): 199-212.




13.    Han, B. and Z. Xu (2006). "Austenite Grain Refinement of Fe-32% Ni Alloy After Intensive Deformation at Low Temperature." Shanghai Metals 28(2): 26-30.

The austenite grains of Fe-32 % Ni alloy were obviously refined after it was alternately compressed in three directions along length, width and thickness at 550DGC with the strain rate of 2 x 10-2s-1. It was considered that the low temperature dynamic recrystallization was completed after observing the micrographs with Light Optical Microscope (LOM), investigating the deformation band with Scanning Electron Microscope (SEM) and analyzing the grain orientations with Electron Back Scatter Diffraction (EBSD). The grain refinement mechanism was that along with the intensive deformation in different directions, the deformed bands became complex and crossed each other to subdivide the austenite grain into several subgrains, and these subgrains were gradually angled to new independent grains with their boundaries being transformed into big angle boundaries in subsequent deformation.




14.    Han, J. H., S. M. Baeck, et al. (2002). Orientation Correction Method of Distorted Samples during In Situ Deformations Using a High Resolution EBSD. ICOTOM 13, Seoul, Korea, Trans Tech Publications Inc.

Sample distortions taking place in plate-type specimens during in-situ shear deformation give rise to a misunderstanding of the rotated orientation of the deformed specimens due to their non-even free surfaces in orientation analysis using an electron backscattered diffraction (EBSD). Orientation analysis of the distorted sample is difficult by the general mapping method using an EBSD. An orientation correction method in determining the orientations of the rotated samples using an EBSD was proposed. The specimens designed for shear deformation test were elongated in an in-situ deformation stage equipped on a field emission gun scanning electron microscope (FEG-SEM). The orientations of the distorted specimens probed using an EBSD were corrected by the proposed orientation correction method.




15.    Han, J.-H., D.-I. Kim, et al. (2004). "Evolution of crystallographic orientations in an aluminum single crystal during tensile deformation." Materials Science and Engineering A 387-389: 235-239.

The evolution of the surface relief and the crystallographic orientations were investigated in a pure aluminum single crystal during in situ uniaxial tensile deformation inside a scanning electron microscope using an electron backscattered diffraction (EBSD) system. The operative slip systems were determined from the EBSD measurement in the deformation bands. Domains of two types form during inhomogeneous deformation showing a different orientation rotation behavior developing with increasing strain. The formation of the domains is caused by the rotation of local crystal areas due to the intersection of the primary and secondary slip systems.




16.    Han, J.-H., K.-K. Jee, et al. (2003). In-situ orientation rotation behavior study during tensile deformation of aluminum single crystal and polycrystal. Designing, Processing and Properties of Advanced Engineering Materials: Proceedings on the 3rd International Symposium on Designing, Processing and Properties of Advanced Engineering Materials, Jeju Island, South Korea.

Orientation rotation behaviors taking place in aluminum single crystal and polycrystal were studied during uniaxial tensile deformation at room temperature. Specimens were elongated in an in-situ deformation stage equipped on a high resolution electron backscattered diffraction (HR-EBSD) system. A series of crystallographic evolution and deformation behavior of concerned areas in the specimens during deformation was directly analyzed using HR-EBSD.




17.    Han, J.-H., K.-K. Jee, et al. (2003). "Orientation rotation behavior during in situ tensile deformation of polycrystalline 1050 aluminum alloy." International Journal of Mechanical Sciences 45(10): 1613-1623.

Microstructural evolutions and orientation rotation behavior taking place during uniaxial tensile deformation at room temperature are studied in polycrystalline 1050 aluminum alloy. Specimens are elongated in an in situ deformation stage equipped in a high-resolution electron backscattered diffraction (HR-EBSD) system. Variations in grain boundary characteristics, such as misorientation and grain boundary distribution, during in situ tensile deformation are analyzed statistically using HR-EBSD. Orientation rotation behavior in individual grains is traced during the whole deformation process. A large number of grains in polycrystalline 1050 aluminum alloy rotate during deformation and are divided into subgrains due to multiple slip. The plane normal directions of individual grains show no remarkable tendency of the orientation rotation during in situ tensile deformation, while the orientation rotation of the tensile direction is found to be strongly dependent on the initial orientation of each grain prior to deformation.




18.    Han, K. S., J. S. Woo, et al. (1999). Through-thickness texture variation in primary recrystallized 3%Si-Fe and its effect on the sharpness of (110)<001> Goss texture. Twelfth International Conference on Textures of Materials (ICOTOM 12), McGill University, Montreal, Canada, NRC Research Press.




19.    Han, W., X. Ren, et al. (2005). "Superplasticity mechanism of duplex stainless steels." Beijing Keji Daxue Xuebao (Journal of University of Science and Technology Beijing) 27(1): 68-71.

The superplasticity mechanism of duplex stainless steels was studied mainly by means of crystallography. On this basis, the Electron Back Scatter Diffraction (EBSD) system was used to obtain the orientation distribution, Tango-mapping and Mambo-pole figures. Microstructural studies associated with transmission electron micrographs observed in the specimens during superplastic deformation suggest that superplastic process occurs mainly by strain-induced phase transformation and dynamic recrystallization, grain boundary sliding and grain re-orientation mechanism.




20.    Hanisch, J., C. Cai, et al. (2005). "Transport measurements and Jc simulations for RABiTS based coated conductors-doping and grain architecture." IEEE Transactions on Applied Superconductivity 15(2): 2794-2797.

The critical current density in RABiTS (rolling assisted biaxially textured substrates) based coated conductors is limited by the network of small-angle grain boundaries up to a texture dependent crossover field Hco. The current flow through this network is percolative in nature and thus depends on misorientation angle distribution, the width and length of the tape, and on the grain shape. These dependencies were simulated using a fast and simple limiting path algorithm on real grain boundary networks obtained by electron backscattering diffraction (EBSD) and cross-checked with transport measurements. A strong dependence of Jc on conductor width below 20 grains and a large increase in Jc for elongated grains was found. Hco of tapes with very sharp cube textures are around 1 T at 77 K. Hence, the intra-grain pinning must be increased for a further improvement of coated conductors applied in higher magnetic fields. With transport measurements on YBa2(Cu1-xZnx)3O7-δ single crystalline thin films, the possibility of a Jc increase due to Zn doping was investigated. Monolayer films with Zn contents up to 0.2%, however, showed a decrease in Jc and Hirr, whereas multilayer films with x=0.017% and x=0.025% Zn) showed an increase in Jc at 77 K.




21.    Hanisch, J., V. S. Sarma, et al. (2004). "Simulation of the critical current density and its dependence on geometrical factors in RABiTS based coated conductors." Superconductor Science and Technology 17(8): 1003-1008.

The conductor width dependence of the critical current density Jc in the grain boundary network occurring in RABiTS based coated conductors is simulated using experimentally obtained electron backscattering diffraction (EBSD) maps and the exponential dependence of the critical current density on the misorientation angle. It is found that a conductor width of around 20 grains (of average size) is sufficient to pass 90% of the maximum current density, independent of texture quality and grain aspect ratio in the current direction. The aspect ratio does however influence the absolute value of Jc, giving higher Jc values for higher aspect ratios. These results are in good agreement with Jc simulations based on purely statistical grain boundary distributions.




22.    Hansen, N. (1985). "Polycrystalline Strengthening." Metallurgical Transactions A 16(12): 2167-2190.




23.    Hansen, N., D. J. Jensen, et al. (1996). Deformation Induced Changes in Microtexture, Local Orientation and Bulk Texture. Eleventh International Conference on Textures of Materials, Xi'an, China, International Academic Publishers.




24.    Hansen, N., X. Huang, et al. (2006). Correlation between texture and structure in high purity Al processed by ARB. 2006 TMS Annual Meeting, San Antonio, Texas, USA.

A high purity Al (99.99%) was deformed by ARB processing with no lubrication to 6 cycles (accumulating an equivalent strain of 4.8). The texture gradients from the sample surface to the sample center were analyzed by EBSD, and four layers classified by different distributions and concentrations of rolling and shear texture components were identified. The microstructures of the four layers were characterized by EBSD and TEM, and differences in the structural parameters including morphology and misorientation were observed, suggesting a relationship between the microstructure and the local texture.




25.    Hansen, S. C. and D. S. Phillips (1983). "Grain-Boundary Microstructures in a Liquid-Phase Sintered Alumina (Alpha-Al2O3)." Philosophical Magazine A 47(2): 209-234.




26.    Harase, J., R. Shimizu, et al. (1991). "Texture Evaluation in the Presence of Precipitates in Fe3%Si Alloy." Acta Metallurgica et Materialia 39: 763-770.




27.    Harase, J., T. Shimizu, et al. (1987). "Study of Micro Texture using SEM and Electron Backscattering." Japanese Institute of Metals Conference Series(62): 502.




28.    Hardy, A., D. Nelis, et al. (2005). "Effect of crystallization parameters on the properties of Bi3.5La0.5Ti3O12 thin films deposited by aqueous chemical solution deposition." Thin Solid Films 492(1-2): 105-113.

Several crystallization parameters were studied during the fabrication of Bi3.5La0.5Ti3O12 thin films by means of a new aqueous chemical solution deposition method. Their effect on the microstructure, orientation, crystal structure and ferroelectric properties of the thin films was examined using scanning electron microscopy, X-ray and electron back-scattering diffraction and ferroelectric hysteresis loop measurements. The thermal treatment was optimized by applying an intermediate crystallization step for each layer, which led to the formation of dense films with ferroelectric properties. Without this intermediate crystallization, the films were shortcircuited due to the high porosity. Subsequently, the effect of the crystallization temperature on Bi3.5La0.5Ti3O12 thin films prepared from precursors containing 10 mol% Bi3+ excess, was looked into. The Pr increased linearly with the crystallization temperature between 600 and 700 degrees C. Finally, the concentration of O2 in the ambient during the crystallization was varied. Hillocking occurred below 10% O2 due to a reaction of the substrate. The ferroelectric properties also deteriorated when crystallization was carried out below a critical O2 partial pressure.




29.    Harland, C. J., J. H. Klein, et al. (1978). "Electron back-scattering patterns in a field emission gun scanning electron microscope." Electron Microscopy.

The electron back-scattering pattern (EBSP) is a simple means of obtaining the crystallographic orientation of samples in the SEM. Kikuchi bands are observed on a fluorescent screen approximately 15 mm in front of a (tilted) sample and shadows, for example of three spherical balls, can be used to obtain orientation determinations accurate to +or-0.5 degrees. A fibre-optic detector of angular diameter <2 thetaB can be used to form images of polycrystalline material with markedly increased grain contrast. These techniques have been transferred onto an ultra-high vacuum SEM equipped with a field emission gun (FEG). The higher brightness of the FEG enables the spot size to be reduced markedly. (6 References).




30.    Harland, C. J., P. Akhter, et al. (1981). "Accurate microcrystallography at high spatial resolution using electron back-scattering patterns in a field emission gun scanning electron microscope." Journal of Physics E 14(2): 175-82.

Electron back-scattering patterns (EBSPS) have been obtained in a field emission gun scanning electron microscope, and the crystallographic information they contain has been shown to come from a small volume <or approximately=20*80*10 nm. A small angle back-scattered electron detector has been used to take pictures with enhanced crystallographic contrast, and is capable of clearly delineating sub-grain boundaries in a Ni (100) crystal with misorientations of order 0.5 degrees. The EBSP technique has been applied to determine epitaxial orientation relationships between sub- mu m crystals grown in situ on a single crystal substrate (Ag/W (110)) with an accuracy of +or-0.3 degrees. (20 References).




31.    Harmer, M. P., H. M. Chan, et al. (1999). Grain Boundary Chemistry and Creep Resistance of Oxide Ceramics. Science of Engineering Ceramics. Pt.2. 2nd Int.Symp., Osaka.

Oversized dopant ions such as yttrium, lanthanum, and neodymium segregate to grain boundaries and reduce the tensile creep rate of a-Al2O3 by 2 or more orders of magnitude. One explanation for this behaviour is that the oversized dopant segregants give rise to a "site-blocking" effect for grain boundary diffusion. Another mechanism that has been speculated involves the change in grain boundary structure caused by dopant ion segregation, producing more abundant special boundaries. In addition, further reduction of creep rate can be obtained by selective co-doping. In this case, grain boundary diffusion is suppressed to such a degree that creep may now be controlled by lattice diffusion. The details of this behaviour can be understood by careful tailoring of the alumina grain boundary chemistry as well as by characterising the grain boundary structure. Results from techniques such as SIMS, STEM, and electron backscattered Kikuchi diffraction (EBKD) analyses, together with computer modelling of segregation behaviour are given.




32.    Harnish, S. F., H. A. Padilla, et al. (2005). "High-Temperature Mechanical Behavior and Hot Rolling of AA795X." Metallurgical and Materials Transactions A 36A(2): 357-369.

High-temperature mechanical behavior and processing performance of 705X aluminum alloys is examined, employing a combination of mechanical testing, microscopy, and computational modeling. We perform hot uniaxial compression tests over a range of temperatures and strain rates and fit the data to power-law constitutive models. These models are supported and expanded by microscopy and calorimetry, which help to elucidate the operating deformation mechanisms and examine damage evolution. The mechanical behavior constitutive relations are implemented in a finite-element code to simulate the hot rolling process. The results of the rolling simulation are used to predict final product crystallographic texture, which is compared with experimental electron backscattered diffraction measurements for model validation. Finally, we propose a parameter to characterize the development of damage during processing. This work provides a solid foundation for the design of thermomechanical processing of these alloys to maximize yield and optimize process performance.




33.    Harper, J. M. E., D. A. Smith, et al. (1985). Microstucture of Niobium Films Oriented by Non-Normal Incidence Ion Bombradment During Growth. Materials Research Society Symposia Proceedings. H. Kurz, G. L. Olson and J. M. Poate, Materials Research Society. 51: 343-348.




34.    Harris, K. E. (1998). "Texture evolution in NiAl." Materials Science and Engineering A 247(1-2): 187-194.

We have investigated texture evolution in stoichiometric NiAl and Ni-49at.%Al–1at.%Ti using orientation imaging microscopy (OIM) and X-ray diffraction. Grain size and orientation were studied after extrusion and after heat treatment, leading to the following model of texture evolution. During extrusion, dynamic recrystallization occurs with a continuing cycle of deformation to produce a <110> fiber texture, nucleation of nearly randomly-oriented grains, and preferential growth of <111> grains. Upon cooling from the extrusion temperature, nucleation continues until the temperature drops below the recrystallization temperature. A <110> fiber texture observed after extrusion suggests the specimen did not fully recrystallize during cooling and the deformation texture is retained. A <111> fiber texture indicates a fully recrystallized microstructure in which significant grain growth has occurred. It has been found that titanium addition increases the recrystallization temperature of NiAl and retards grain growth resulting in the retention of the <110> fiber texture.




35.    Hasegawa, M., M. Yamamoto, et al. (2003). "Formation mechanism of texture during dynamic recrystallization in γ-TiAl, nickel and copper examined by microstructure observation and grain boundary analysis based on local orientation measurements." Acta Materialia 51: 3939-3950.

Texture formation in γ-TiAl, nickel and copper during dynamic recrystallization (DRX) in compression deformation is studied. The formation process is discussed in relation to the mechanism of new grain formation during DRX. It is found that the behavior of texture formation varies depending on Z (the value of the Zener-Hollomon parameter) and the kind of material. During deformation in low Z conditions, sharp fiber texture develops in γ-TiAl, suggesting that strain-induced grain boundary migration is predominant in the new grain formation. No sharp texture is seen in nickel and copper after the dynamic recrystallization in low Z conditions. However, microstructure observation suggests that new grains are also generated by strain-induced grain boundary migration in these two pure metals. It is found that the difference of texture formation between γ-TiAl and the other two pure metals is ascribed to the difference in the frequency of twinning during grain boundary migration; texture develops only when the frequency is low, which is the case of γ-TiAl.




36.    Hashimoto, N., N. Yoshinaga, et al. (1996). Influence of Recrystallization Temperature on Nucleation Orientation During Recrystallization in Ultra Low-Carbon Cold-Rolled Sheet Steels. Eleventh International Conference on Textures of Materials, Xi'an, China, International Academic Publishers.




37.    Hasija, V., S. Ghosh, et al. (2003). "Deformation and creep modeling in polycrystalline Ti–6Al alloys." Acta Materialia 51: 4533-4549.

This paper develops an experimentally validated computational model for titanium alloys accounting for plastic anisotropy and time-dependent plasticity for analyzing creep and dwell phenomena. A time-dependent crystal plasticity formulation is developed for hcp crystalline structure, with the inclusion of microstructural crystallographic orientation distribution. A multi- variable optimization method is developed to calibrate crystal plasticity parameters from experimental results of single crystals of α-Ti–6Al. Statistically equivalent orientation distributions of orientation imaging microscopy data are used in constructing the polycrystalline aggregate model. The model is used to study global and local response of the polycrystalline model for constant strain rate, creep, dwell and cyclic tests. Effects of stress localization and load shedding with orientation mismatch are also studied for potential crack initiation.




38.    Hassani, S., A. Lusson, et al. (2003). "Seed-free growth of (1 1 1) oriented CdTe and CdZnTe crystals by solid-state recrystallization." Journal of Crystal Growth 249: 121-127.

Solid-state recrystallization (SSR) is proposed as a novel method of CdTe bulk crystal growth which allows one to overcome the difficulties met in the growth of the compound which result from the ionic character of the Cd–Te chemical bond. A three-step strategy for CdTe SSR growth is described where the production of CdTe provides a source for the subsequent growth by sublimation of polycrystalline boules which are finally submitted to SSR. The material obtained after each step is characterized electrically, optically and chemically. Large CdTe crystals showing good structural properties have been obtained from this SSR technique, which is demonstrated to be also convenient for the growth of CdZnTe crystals.




39.    Hata, S., T. Hashimoto, et al. (1999). "Microstructures in Ti50Al45Mo5 alloy powders prepared by the plasma-rotating-electrode-process (PREP)." Engineering Sciences Reports, Kyushu University 21(1): 9-14.

Microstructures in rapidly solidified Ti50Al45Mo5 alloy powders prepared by the plasma-rotating-electrode-process (PREP) were investigated by means of scanning electron microscopy (SEM), electron backscattering diffraction (EBSD) and transmission electron microscopy (TEM). It was found that the PREP alloy powders contain the ordered alpha2 (hcp-based D019 structure) and the beta2(bcc-based B2 structure) phases, and their microstructures vary considerably with locations in the powder. The inhomogeneity in microstructures is explained in terms of the difference in cooling rate depending on the depth from the powder surface. (12 References).




40.    Haušild, P., C. Berdin, et al. (2004). "Prediction of cleavage fracture for a low-alloy steel in the ductile-to-brittle transition temperature range." Materials Science and Engineering A 391: 188-197.

This paper attempts to predict the cleavage fracture probability for a low-alloy bainitic steel. Fractographic analysis of broken compact tension (CT) and Charpy V-notch (CVN) specimens was performed. An evolution of physical mechanisms of cleavage initiation was found: crackedparticle-induced cleavage was observed at low temperature, whereas a plasticity-induced mechanism was assumed as temperature increases. To take into account these observations, temperature-dependent Weibull parameters were used in the Beremin model. The introduction of a threshold cleavage stress was necessary to account for the skewness of the fracture probability distribution. With these parameters identified on the instrumented Charpy data set, the fracture toughness Jc was successfully predicted in the DBTT range.




41.    Hausild, P., M. Karlík, et al. (2005). "Fractographic analysis of the crack growth in the Fe3Al based intermetallic alloy." Intermetallics 13: 217-225.

The fracture properties of the hot rolled Fe–28Al (at.%) intermetallic alloy with the addition of chromium and cerium were studied. The fracture toughness and the fatigue crack growth rate (da/dN- δK curves) were measured. Fractographic analysis carried out on fracture surfaces of ruptured specimens revealed several failure mechanisms of crack propagation. Both in static and cyclic loading the main failure mechanism is transgranular cleavage. The fatigue fracture surface shows a varied micromorphology. Besides transgranular cleavage, ductile fatigue striations and brittle striations were found. The influence of the microstructure (especially of the crystallographic orientation and the shape of grains) on the crack growth was characterized by means of electron backscattering diffraction.




42.    Hayakawa, A., M. Muraki, et al. (1998). "The Changes of Grain Boundary Character Distribution During the Secondary Recrystallization od Electrical Steel." Acta Materialia 46(3): 1063-1073.




43.    Hayakawa, M., S. Matsuoka, et al. (2005). "Development of observation method for tempered martensite microstructure using chemical mechanical polishing technique." Materials Transactions 46(11): 2443-2448.

A new observation method was developed for visualizing microstructure on a chemical mechanically polished (CMP) surface for tempered martensite of JIS-SCM440, a medium-carbon steel. The CMP and an electropolished (EP) surfaces were observed using an atomic force microscope (AFM) and a field emission type-scanning electron microscope (FE-SEM), respectively. AFM images, FE-secondary and backscattered electron images and electron backscattered patterns (EBSP) were obtained for the CMP and EP surfaces. The AFM and FE-secondary electron images of the EP surface clearly visualized martensite blocks and cementite particles, since unevenness corresponding to blocks and cementite particles was created by electropolishing. On the other hand, the AFM images of the CMP surface revealed that the CMP process produced a very smooth surface with unevenness not exceeding 10 nm. The FE-backscattered electron images of the CMP surface only visualized the crystal misorientation of the martensite matrix microstructure, since the images are not influenced by surface unevenness. The CMP surface is more appropriate than the EP surface for EBSP measurements, since the CMP surface is smoother than that of the EP surface. Blocks with a high-angle boundary exceeding 15 could be recognized by EBSP mapping, but laths with a low-angle boundary below 3°could not.




44.    Hayakawa, Y. and J. A. Szpunar (1996). A Mechanism of the Secondary Recrystallization in Grain-Oriented Electrical Steel. Eleventh International Conference on Textures of Materials, Xi'an, China, International Academic Publishers.




45.    Hayakawa, Y. and M. Kurosawa (2002). "Orientation relationship between primary and secondary recrystallized texture in electrical steel." Acta Materialia 50(18): 4527-4534.

Cube ({100}<001>) texture is developed through secondary recrystallization when rolling direction is changed towards tha transverse direction at the final stage of cold-rolling of grain-oriented electrical steel. The development of the dube texture is discussed, stressing the role of high-energy boundary having the misorientation angle between 20 and 45°, which was used for the explanation of the development of Goss ({100}<001>) texture in our previous works. The high-energy boundary has more structural defects, which are linked to high mobility and high grain boundary diffusion rate. Quicker coarsening of precipitates enables high-energy boundaries to move earlier than other boundaries during final annealing. A texture component that has the highest frequency of high-energy boundary can be a main component through selective growth during secondary recrystallization. Textures different from Goss can also be predicted by analyzing the frequency of high-energy boundaries in the primary recrystallized texture. The growth model based on Coindicent Site Lattice (CSL) boundaries and another model based on Orientation Pinning (OP) are tested, but these models cannot provide a consistent explanation in the present experiment. Published by Elsevier Science Ltd. All Rights reserved.




46.    Hayakawa, Y., M. Kurosawa, et al. (2002). Abnormal Texture of Grain-Oriented Electrical Steel under High Cold Rolling Reduction. ICOTOM 13, Seoul, Korea, Trans Tech Publications Inc.

The effect of the final cold-rolling reduction on electrical steels with different inhibitors is investigated. In strong inhibition system, complete secondary recrystallization of Goss texture is obtained under the final cold-rolling reduction from 50% to 87%. The intensity of Goss texture enhances according to the increase of the cold-rolling reduction. In weak inhibition system, secondary recrystallization fails to occur under the final cold-rolling reduction over 70%, instead, abnormal grain size with a wide grain-size distribution appears. Approximately, grain size ranges from 0.03 mm to 10 mm. The orientation of the abnormal texture is investigated using EBSP. Coarse grains over 1 mm have {12, 4, 1}<148>, {100}<001> or Goss orientations. Fine grains under 0.10 mm have {411}<148> or {111}<112> orientations. We previously proposed the mechanism of the secondary recrystallization stressing the role of high-energy boundary with a misorientation angle between 20 and 45 degrees. Goss orientation has the highest frequesncy of high-energy boundary in the primary recrystallized texture. High-energy boundary has a high mobility under the presence of inhibitors. In case of weak inhibition system, primary recrystallized grain has a coarse grain size. The driving force for the secondary recrystallization is small, and the selectivity of the mobile boundary considered to be reduced. In such a case, grains other than Goss grain can grow. Coarse grains over 1 mm have considerably high value of the high energy boundary around them, thus enhanced growth is caused by the high mobility of the high-energy boundary. The orientation of the fine grains under 0.10 mm is a main component of primary recrystallized texture. Fine grain is considered to grow by the size effect.




47.    Hayakawa, Y., T. Imamura, et al. (2003). "Observation of cold-rolling texture and partially recrystallized texture in polycrystalline 3 pct Si-Fe by high-resolution electron backscattered diffraction." Metallurgical and Materials Transactions A 34(2): 403-408.

Cold-rolling texture and partially recrystallized texture of polycrystalline 3 pct Si-Fe were investigated using high-resolution electron backscattered diffraction (EBSD) method. From the measurement on a deformed grain with {211}<011> similar to {111}<011> orientations, deformation bands with {12 4 1}<014> orientation were found. It turned out that the orientation rotation relationship between deformation bands and surrounding deformed grain can be explained by the activation of the slip system, which has a common slip plane with an adjacent grain. Oriented nucleation of recrystallized grains with {12 4 1}<014> orientation was observed in a deformed grain with {211}<011> similar to {111} <011> orientation. Exactly the same orientation relationship that was observed between deformed grain and the deformation bands was also observed between the deformed grain and the recrystallized grain. A hypothesis that recrystallization nuclei are generated directly from the deformation bands formed by an activation of the slip system that has a common slip plane of neighboring deformed grains was proposed from the present experimental results.




48.    Hayakawa, Y., T. Takamiya, et al. (1999). Relation between grain boundary mobility and grain boundary character in Fe-3%Si. Twelfth International Conference on Textures of Materials (ICOTOM 12), McGill University, Montreal, Canada, NRC Research Press.




49.    Hayama, A. O. F. and H. R. Z. Sandim (2006). "Annealing behavior of coarse-grained titanium deformed by cold rolling." Materials Science and Engineering A 418(1-2): 182-192.

This work describes the annealing behavior of coarse-grained titanium deformed by cold rolling. A longitudinal section of a high-purity coarse-grained titanium ingot obtained by double electron beam melting (EBM) was cold rolled to thickness reductions varying from 10 to 70%. Vacuum annealing was performed at 500, 700 and 800 °C for 1 h (α-phase field). Microstructural characterization was performed in both cold rolled and annealed specimens using light optical microscopy (LOM), scanning electron microscopy (SEM), electron backscattered diffraction (EBSD) and Vickers microhardness testing. Orientation effects associated with the coarse initial grain structure of oligocrystalline titanium were observed during annealing. In certain regions the microstructure of annealed titanium consists of alternating bands of recrystallized grains with local variations in grain size and texture and a few elongated areas marking the presence of individual grains softened by recovery.




50.    Hayama, A. O. F., H. R. Z. Sandim, et al. (2004). "Annealing behavior of the ODS nickel-based superalloy PM 1000." Materials Science and Engineering A 371(1-2): 198-209.

PM 1000 is a powder-metallurgy (P/M) nickel-based superalloy containing about 1% (volume) of fine and uniformly dispersed incoherent particles in an austenitic matrix. In the present paper, we have investigated the annealing behavior of rods deformed by cold swaging to reductions of 24 and 44% followed by annealing in temperatures varying from 800 to 1350 degrees C. The microstructural changes were followed by channeling contrast in the scanning electron microscopy (SEM), electron backscattering diffraction (EBSD), and transmission electron microscopy (TEM). Results show that discontinuous recrystallization and extended recovery are responsible for the softening of this alloy. A few grains found preferentially at grain boundary regions and within deformation heterogeneities like shear bands are able to grow corresponding to a recrystallized volume fraction lower than 10%. These new grains are arranged in colonies having a significant amount of annealing twins with Sigma 3-symmetry boundaries. The pinning effect on boundaries exerted by hard non-deformable particles (Zener drag) tends to suppress growth of most recrystallized grains. In the less deformed regions of the microstructure, a particle-stabilized subgrain structure is present and further softening is not significant even when longer annealing is performed.




51.    Hayashi, K., Y. Ikuhara, et al. (2004). "Direct characterization of grain-boundary electrical activity in doped (Ba0.6Sr0.4)TiO3 by combined imaging of electron-beam-induced current and electron-backscattered diffraction." Journal of the American Ceramic Society 87(6): 1153-1156.

Simultaneous measurements of remote electron beam induced current (REBIC) and orientation imaging microscopy (OIM) in a scanning electron microscope (SEM) have been applied to a polycrystalline (Ba0.6Sr0.4)TiO3 with a positive temperature coefficient of resistivity (PTCR) to elucidate a grain-boundary character dependence of the potential barrier formation. The absence of electrical activity in a coherent S3 twin boundary is clearly imaged. The resistivity of individual grain boundaries estimated from a resistive contrast image is interpreted in terms of geometrical coherency, which is defined by the degree of coincidence in the reciprocal lattice points.




52.    He, C. S., Y. D. Zhang, et al. (2005). Characteristics of Recrystallization Texture Evolution in High Magnetic Field for Interstitial Free (IF) Steel Sheet. Textures of Materials - ICOTOM 14, Leuven, Belgium, Trans Tech Publications.

High magnetic field is applied with the field direction parallel to the rolling direction during annealing of a cold rolled IF steel sheet. Results of X-ray ODF analysis show that, magnetic field annealing retards the normal recrystallization texture evolution for the IF steel sheet. It is worth noting that an abnormal increase of orientation intensity at {100}<110> is found after magnetic annealing for 25min at 650°C. When the magnetic field strength is increased from 10 Tesla to 14 Tesla, the α-fiber is further strengthened, especially the {100}<110> component. Combined with EBSD analysis results, it is considered that the magnetic field does not change the mechanism of recrystallization texture evolution for the IF steel sheet in the present case.




53.    He, H., T. Czerwieca, et al. (2003). "Effect of grain orientation on the nitriding rate of a nickel base alloy studied by electron backscatter diffraction." Surface and Coatings Technology 163-164: 331-338.

Electron backscatter diffraction is a rather new and powerful technique that provides local orientation. In this paper we present an investigation on cross-sections of a nickel base alloy (Inconel 690) treated by low temperature plasma assisted nitriding. The studied alloy presents non-uniform nitrided layer thickness from grain to grain. A linear relationship is found between the thickness of the nitrided layer within a surface grain and the minimum angle between nitriding direction and the <1 0 0> crystal direction. This angle characterizes the orientation of the grain beneath the nitrided layer. Deeper diffusion is observed in grains with orientation close to <1 0 0> than in those grains with orientation close to <1 1 1>. An anisotropic dependence of the stress on the strain is proposed to explain these phenomena. The consequences of the interpretation of X- ray diffraction pattern and nitrogen depth profiles of the nitrided layer are discussed.




54.    He, T., Y. D. Liu, et al. (2005). "Microtexture evolution of partially recrystallised interstitial free steel." Materials Science and Technology 21(12): 1436-1439.

A partially recrystallised extrathinned interstitial free steel has been investigated by X-ray diffraction and electron backscattered diffraction (EBSD). The results show that the orientation of recrystallisation nuclei plays an important role in the process of recrystallisation texture formation. The growth of the < 111 > llnormal direction (ND) is very rapid compared with its nucleation.




55.    He, T., Y. D. Liu, et al. (2005). Study on the Micro Mechanism of Recrystallization Texture Formation in Cold-rolled IF Steel sheet. Textures of Materials - ICOTOM 14, Leuven, Belgium, Trans Tech Publications.

An experimental setup was designed to study the recrystallization kinetics of Interstitial Free (IF) steel in this work. The 80% cold rolled IF steel foils are heated rapidly to 680°C, 730°C and 780°C by a salt bath. The recrystallization kinetic curves were obtained by the quantitative analysis of texture components, microstructures and EBSP (electron back-scattering patterns) measurements. With the help of EBSD, the orientations of the recrystallization nuclei are determined. The growth rule of the recrystallization nuclei was analyzed statistically. The effect of nucleus orientation on the formation of the recrystallization texture was investigated.




56.    He, Y., S. Godet, et al. (2004). Crystallographic relationships between FCC and BCC crystals: a study using EBSD techniques. 2nd International Conference on Texture and Anisotropy of Polycrystals (ITAP 2), Metz, France, Balaban Publishers; Scitec Publications, Switzerland.

The mechanisms governing the formation of transformation textures during the austenite-to-ferrite transformation are the subject of major debate. In this study, two extreme cases were examined: those of undeformed and deformed austenite. The first involves the transformation of austenite into Widmanstatten ferrite under "equilibrium" conditions in the Gibeon iron-nickel meteorite. This meteorite passed through the transformation at the rate of a few degrees per million years. Such cooling rates cannot of course be reached under laboratory conditions. The second concerns the transformation of hot rolled austenite after a quench into the bainite temperature range. These two behaviors were investigated by means of optical microscopy and electron backscatter diffraction (EBSD) techniques. The orientations of both the parent and product phases were measured and the orientation relationships are represented in Rodrigues-Frank (R-F) space. From the orientation of a particular FCC crystal, the crystallographic orientations of the product BCC crystals can be predicted according to the Bain, Kurdjumov-Sachs (K-S) and Nishiyama-Wassermann (N-W) correspondence relationships. Comparison of the predicted and measured orientations reveals that the Bain rotation is never observed; the K-S and N-W relationships are both observed and there is a continuous distribution of orientations between the exact K-S and N-W positions. The formation of preferred orientation under non-equilibrium conditions is scrutinized. These results are compared to recent models accounting for variant selection.




57.    He, Y., S. Godet, et al. (2005). Crystallographic Relationships Between Taenite and Kamacite in the Gibeon Meteorite. Solid to Solid Phase Transformations in Inorganic Materials 2005, Phoenix, Arizona, USA, TMS.

The orientations of kamacite (α) lamellae transformed from a single prior-taenite (γ) grain were measured by analyzing the EBSD (electron backscatter diffraction) patterns; these were compared with the orientation of the retained taenite on pole figures. The orientation relations between the a and γ phases in the plessite (a two-phase mixture of the α and γ) regions were also charcterized. All the variants corresponding to the Kurdjumov -Sachs (K-S) and Nishiyama-Wassermann (N-W) relationships were observed, as were the intermediate reflections located between the coplanar K-S and N-W variants. The local misorientations between individual fcc and bcc crystals along their common interfaces were computed and it was found that the exact orientation relationship varies along the boundary, a significant proportion of which does not satisfy any of the relations exactly. Orientation variations of up to about 10 degrees were observed within individual kamacite lamellae; these usually covered the range from one K-S variant, through the N-W position, to the other coplanar K-S variant. Numerous Neumann bands (mechanical twins) were also detected within the kamacite lamellae, which indicate that some sort of deformation occurred during or after the γ-to-α transformation.




58.    He, Y., S. Godet, et al. (2005). A Study of the γ-to-α Transformation Using EBSD Techniques. Textures of Materials - ICOTOM 14, Leuven, Belgium, Trans Tech Publications.

The crystallographic relationship between the γ and α phases in samples of the Gibeon meteorite and a TRIP steel was investigated by means of EBSD techniques. The orientations of the two phases were measured and are represented in pole figures. The results are compared to predictions made on the basis of the Bain, Kurdjumov-Sachs (K-S), Nishiyama- Wassermann (NW), Greninger-Troiano (G-T) and Pitsch orientation relationships. The local misorientation between individual fcc and bcc crystals along their common interface was measured to demonstrate the way in which the exact orientation relationship varies along the boundary. The local orientations within lamellae and laths of kamacite and bainite are compared to that in recrystallised ferrite polygons. The occurrence of variant selection during the transformation of deformed austenite is analyzed using a recent dislocation- based model.




59.    He, Y., S. Godet, et al. (2005). Variant Selection during the Transformation of Deformed Austenite in a Niobium Bearing TRIP Steel. Textures of Materials - ICOTOM 14, Leuven, Belgium, Trans Tech Publications.

The transformation behavior of a 0.22wt%C-1.50wt%Mn-1.56wt%Si-0.045wt%Nb steel was studied after controlled rolling. Deformation below the no-recrystallisation temperature was employed to deform the prior austenite. During bainitic holding, some of the austenite was retained due to the enrichment of carbon in this phase. Using automated EBSD techniques, both the retained austenite and bainite orientations were measured and the orientation relationships between these phases are represented in Rodrigues-Frank space. The specific orientations predicted by the Bain, Kurdjumov-Sachs and Nishiyama-Wassermann relationships are compared with the measurements and the occurrence of variant selection is discussed.




60.    He, Y., S. Godet, et al. (2005). "Representation of misorientations in Rodrigues-Frank space: Application to the Bain, Kurdjumov-Sachs, Nishiyama-Wassermann and Pitsch orientation relationships in the Gibeon meteorite." Acta Materialia 53(4): 1179-1190.

The three classical orientation relationships describing the γ-to-α transformation, namely the Bain, Kurdjumov-Sachs (K-S) and Nishiyama-Wassermann (N-W), are represented in Rodrigues-Frank (R-F) space. Two alternative reference systems are used to highlight the differences between the three types of misorientation. Some observations obtained on the Gibeon meteorite are analyzed using the two classes of reference system to reveal features of the transformation under conditions of very slow cooling. It is shown that the Bain correspondence relations are never satisfied, while the measurements fall in the full range of direction parallel conditions extending from the K-S to the N-W. The crystallographic features of the Pitsch orientation relation are presented in R-F space in Appendix A. The experimental observations conform to this type of transformation to a considerably lesser extent than to the classical K-S and N-W relations. Copyright 2004 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.




61.    He, Y., S. Godet, et al. (2006). "Crystallographic relations between face- and body-centred cubic crystals formed under near-equilibrium conditions: Observations from the Gibeon meteorite." Acta Materialia 54(5): 1323-1334.

The orientations of the kamacite lamellae formed from a single prior-taenite grain were measured by analysing the electron backscatter diffraction patterns obtained using scanning electron microscopy. These are shown to be close to the Kurdjumov–Sachs and Nishiyama–Wassermann relations and their intermediate, i.e., the Greninger–Troiano relation. The orientations of the α grains in the plessite regions were also measured and these were found to be continuously distributed around the Bain circles formed by the variants of the common correspondence relationships, including the Pitsch one in this case. The local misorientations between individual face- and body-centred cubic crystals along their common interfaces were measured. These can be characterized by the orientation relationships mentioned above as long as a certain amount of tolerance is allowed. Orientation variations within individual kamacite lamellae were also analysed. The crystallographic data support the view that somewhat different mechanisms are involved in the formation of Widmanstätten structures and of the plessite in meteorites.




62.    He, Y., S. Godet, et al. (2006). "Observations of the Gibeon meteorite and the inverse Greninger–Troiano orientation relationship." Journal of Applied Crystallography 39: 72-81.

All the possible parallelism conditions associated with low-index crystallographic planes and directions in face- and body-centred cubic crystals are enumerated in terms of their minimum angle–axis misorientations. These include the Kurdjumov–Sachs (K-S), Nishiyama–Wassermann (N-W) and Pitsch orientation relationships, which are expressed in terms of close-packed (and near-close-packed) planes, close-packed directions, or both in the two crystal systems. By classifying these into either coplanar or codirectional relationships, it is possible to specify intermediate relations with either high-index directions or planes. In such a way, the Greninger–Troiano (G-T) relationship is approximated as a coplanar relation lying between the K-S and N-W relations. Based on geometric symmetry, a further correspondence relationship, which falls into the codirectional category and is located between the K-S and Pitsch relations, is represented both in pole-figure form and in Rodrigues–Frank space. It is referred to here as the inverse G-T, or G-T0. Experimental evidence from the plessite regions of the Gibeon meteorite is presented to support the validity of this relationship. It is shown that, in plessite, all the well known models, as well as their intermediates, are applicable to the γ-to-α transformation. By contrast, in the Widmanstätten portions, the misorientations are largely limited to the K-S, G-T and N-W relations.




63.    He, Z. M., S. B. Fu, et al. (1987). "Improved Work-Hardening Ability and Wear-Resistance of Austenitic Manganese Steel Under Non-Severe Impact-Loading Conditions." Wear 120(3): 305-319.




64.    Heason, C. P. and P. B. Prangnell (2002). Texture Evolution and Grain Refinement in Al Deformed to Ultra-High Strains by Accumulative Roll Bonding (ABR). ICOTOM 13, Seoul, Korea, Trans Tech Publications Inc.

AA1100 sheet was severely deformed to true strains of ~ 10, by accumulative roll bonding (ARB). High resolution EBSD and bulk texture analysis has been used to study the development of the texture and deformation structure. Even at very high strains it has been found that ultra-fine grains were not produced homogeneously through the sheet thickness. A strong texture developed during ARB, which resulted from the weakening of the Brass {011}<112> and S{123}<634> rolling components in favour of a very strong Cu {112}<111> and Shear texture {001}<110>. This texture develops because the surface shear texture rotates to Cu when moved to the sheet centre during each bonding cycle. It is thought that, despite the extremely high plastic strains achieved, the development of a strong texture prevents full grain refinement to the submicron scale.




65.    Heason, C. P. and P. B. Prangnell (2004). The effect on grain refinement of developing a strong texture in an UFG Al-0.13 Mg alloy severely deformed by ECAE. Ultrafine Grained Materials III (as held at the 2003 TMS Annual Meeting), Charlotte, North Carolina, USA.

A single phase Al-0.13%Mg alloy has been severely deformed to a strain of similar to 10 at room temperature by ECAE, producing a submicron grain structure (>70% HAGB) and a weak texture. The ECAE billets were subsequently deformed by both conventional rolling and ARB processing, to produce sheet material with strong rolling textures and, in the case of ARB, an additional shear {001} <110> texture. From EBSD analysis it has been found that, although the grain size initially decreases and HAGB fraction increases at low rolling strains, as the texture strengthens during continued deformation the HAGB fraction then starts to decrease. This is associated with the appearance of coarse, unrefined regions in the microstructure. It is thought that this is caused by the rotation of neighbouring grains to the same end orientation, determined by the dominant texture component, thus reducing misorientations across HAGBs.




66.    Hebesberger, T., E. Schafler, et al. (2001). "Electron Back-Scatter Diffraction and Synchrotron X-Ray Peak Profile Analysis as Tools for Microstructural Characterization of Large-Strain Work-Hardened Metals." Zeitschrift fur Metallkunde 92(5): 410-416.




67.    Hebesberger, T., H. P. Stüwe, et al. (2005). "Structure of Cu deformed by high pressure torsion." Acta Materialia 53(2): 393-402.

Pure copper is deformed by high pressure torsion and the resulting microstructure is studied. Small structural elements are formed. Their size decreases with increasing strain and reach a steady-state. The misorientation between neighbouring structural elements increases with strain and finally reaches a nearly random distribution. The steady-state size decreases with increasing pressure and decreasing temperature. The shape of the elements suggests the continuous formation of new elements during steady-state deformation. This would be a process similar to dynamic recrystallisation.




68.    Hecht, U., V. T. Witusiewicz, et al. (2005). "Orientation relationship in univariant Al-Cu-Ag eutectics." Transactions of the Indian Institute of Metals 58(4): 545-551.

Coupled, regular eutectic growth of alpha (Al) and Al2Cu from ternary Al-Cu-Ag liquid alloys is investigated with focus on the orientation relationship observed in unidirectionally solidified, polycrystalline, bulk samples. The results of extensive EBSD-mappings for both planar and cellular eutectics are presented and crystalline anisotropy is shown to have a determining influence on the evolution of cellular eutectic patterns. The topologic anisotropy, however, associated to the lamellar structure of the eutectic, is shown to be responsible for the early stages of destabilization of the initially planar solid/liquid interface.




69.    Hector, L. G. J., Y.-L. Chen, et al. (2004). "Texture characterization of autogenous Nd:YAG laser welds in AA5182-O and AA6111 T4 aluminum alloys." Metallurgical and Materials Transactions A 35A(9): 3032-3038.

This article reports a study of texture characterization in Nd:YAG laser welds of AA5182-O and AA6111-T4 alloys. Electron backscattering diffraction (EBSD) in the scanning electron microscope was used to determine the texture. The determination was made as a function of thickness through the sample. The results show that the welds can develop significant texture. In particular, the columnar grains that grow from the base metal into the weld have a strong 001 texture along the direction of growth.




70.    Heiberg, G. and L. Arnberg (2001). "Investigation of the microstructure of the Al-Si eutectic in binary aluminum-7 wt% silison alloys by electron backscatter diffraction (EBSD)." Journal of Light Metals 1: 43-49.

Binary aluminum-7 wt% silicon alloys with and without strontium modification have been cast with a cooling rate of 0.2-0.6°C/s. The level of impurities has been kept at a minimum. The crystallographic orientation of the dendritic and eutectic aluminum as well as the eutectic silicon has been studied using electron backscatter diffraction (EBSD).The crystallographic orientation of the aluminum within the eutectic is found to be strongly influenced by the orientation of neighbouring dendrites in unmodified and Sr-modified alloys. The crystallographic orientation of the silicon phase in the eutectic shows that silicon flakes/fibers within one eutectic colony can often be related to each other by the misorientation characteristic of twinning. Within one Sr-modified eutectic colony, silcon fibers are often found to have a common (110) direction. Aluminum has been found to have a (100) or a (110) direction parallel to the (110) direction of the Si fibers.




71.    Heiberg, G., K. Nogita, et al. (2002). "Columnar to equiaxed transition of eutectic in hypoeutectic aluminium–silicon alloys." Acta Materialia 50: 2537-2546.

Directional solidification of unmodified and strontium modified binary, high-purity, aluminium–7 wt% silicon and commercial A356 alloys has been carried out to investigate the mechanism of eutectic solidification. The microstructure of the eutectic growth interface was investigated with optical microscopy and Electron Backscattering Diffraction (EBSD). In the commercial alloys, the eutectic solidification interface extends in the growth direction and creates a eutectic mushy zone. A planar eutectic growth front is observed in the high-purity alloys. The eutectic aluminium has mainly the same crystallographic orientation as the dendrites in the unmodified alloys and the strontium modified highpurity alloy. A more complex eutectic grain structure is found in the strontium modified commercial alloy. A mechanism involving constitutional undercooling and a columnar to equiaxed transition explains the differences between pure and commercial alloys. It is probably caused by the segregation of iron and magnesium and the activation of nucleants in the commercial alloy.




72.    Heidelbach, F., B. Holtzman, et al. (2005). Textures in experimentally deformed olivine aggregates: the effects of added water and melt. Textures of Materials - ICOTOM 14, Leuven, Belgium, Trans Tech Publications.

The texture development in experimentally sheared aggregates of olivine was monitored as a function of increased water content and added melt. In dry samples, an alignment of {010} with the shear plane and <100> and <001> with the shear direction, respectively, was observed, consistent with intracrystalline glide on the (010)[100] and (010)[001] slip systems. Samples with high water content showed consistently stronger textures of the (010)[100] component for comparable shear strains indicating that water may especially ease glide on this slip system. Samples with added melt showed an increased alignment of {010} and <001> subparallel to shear plane and shear direction respectively, whereby the maxima were consistently rotated 10 to 20° against the sense of shear. This type of texture can be explained by a combination of increased glide on the (010)[001] slip system in combination with a partitioning of the strain between melt rich bands and relatively melt free regions in the sample. Physical anisotropies calculated from the textures indicate that increased water content causes enhanced anisotropy for longitudinal and transverse seismic waves. The addition of melt on the other hand may change the type of anisotropy that develops during deformation, but does not significantly change the magnitude of anisotropy compared to samples of pure olivine.




73.    Heidelbach, F., H.-R. Wenk, et al. (1996). "Orientation and Misorientation Characteristics of Annealed, Rolled and Recrystallized Copper." Materials Science and Engineering A 215(1-2): 39-49.




74.    Heidelbach, F., K. Kunze, et al. (2000). "Texture Analysis of a recrystallized quartzite using electron-diffraction in the scanning electron- microscope." Journal of Structural Geology 22(1): 91-104.

The microstructure and crystallographic preferred orientation (texture) of a recrystallized quartzite from the Bergell Alps was quantitatively investigated using automated indexing of electron backscattered patterns (EBSP). The results are displayed in orientation maps of the microstructure and orientation as well as misorientation distribution functions. The orientation distribution function derived from EBSP compares excellently with texture data derived from independent neutron diffraction experiments. The misorientation distribution function of next neighbors reveals strong maxima for small angle grain boundaries (subgrain boundaries) and the Dauphine  twin correlation. The Dauphine twins, which are generally not detectable optically, are not correlated with specific maxima in the orientation distribution function. Their origin and their role during recrystallization is discussed. During recrystallization no other preferred high angle misorientations developed. The frequent occurrence of small angle grain boundaries indicates progressive subgrain rotation as a recrystallization mechanism. # 1999 Elsevier Science Ltd. All rights reserved.




75.    Hejna, J. (1985). "Divergent-Beam X-Ray-Diffraction in the Scanning Electron-Microscopy and its Use for the Study of the Semiconductor Epitaxial Layers." Scanning Electron Microscopy 1985(P3): 1103-1108.




76.    Helary, D., O. Dugne, et al. (2006). "EBSD investigation of SiC for HTR fuel particles." Journal of Nuclear Materials 350(3): 332-335.




77.    Henrie, B. L., T. A. Mason, et al. (2004). "A semiautomated electron backscatter diffraction technique for extracting reliable twin statistics." Metallurgical and Materials Transactions A 35A(12): 3745-3751.

A framework has been developed for extracting reliable twin statistics from a deformed microstructure using crystallographic twin identification techniques with spatially correlated electron backscatter diffraction (EBSD) data. The key features of this analysis are the use of the mathematical definition of twin relationships, the inclination of the common K1 plane at a twin boundary, and the correct identification of the parent orientation in a parent/twin pair. Methods for identifying the parent in a parent/twin pair will be briefly discussed and compared. Twin area fractions are then categorized by operative twin systems, number of active twin variants in each system, and corrected twin widths. These statistics are reported here for α -zirconium samples deformed in quasi-static four-point bend beams and in a 100 m/s Taylor cylinder impact test. Analysis of the statistics also begins to reveal the roles that deformation rate and relative orientation of the boundary conditions to the material's symmetry axes play in determining the twinning activity that accommodates the imposed boundary conditions. These improved twin statistics can help quantify the deformation processes in materials that deform by twinning as well as serve to provide better validation of proposed models of the deformation processes.




78.    Henrie, B. L., T. A. Mason, et al. (2005). Automated Twin Identification Technique for use with Electron Backscatter Diffraction. Textures of Materials - ICOTOM 14, Leuven, Belgium, Trans Tech Publications.

Historically, twinning classification has been obtained by optical microscopy, bulk x-ray and neutron diffraction, and transmission electron microscopy (TEM). Recent research has shown that automated electron backscatter diffraction (EBSD) can be used to quantify twin content and thereby greatly improve the reliability of twinning statistics. An automated twin identification technique for use with EBSD has facilitated a greater understanding of deformation twinning in materials. The key features of this automated framework are the use of the crystallographic definition of twin relationships, and the correct identification of the parent orientation in a parent/twin pair. The complex nature of the parent/twin interactions required the use of a voting scheme to correctly identify parent orientations. In those few cases where the voting scheme was unable to determine parent orientation (< 2%) the algorithm allows for manual selection. Twin area fractions are categorized by operative twin systems along with secondary and tertiary twinning. These statistics are reported for deformation and annealing twin populations in deformed α-zirconium and asannealed 316L stainless steel, respectively. These improved twin statistics can help provide insight into the effect of deformation processes on microstructural evolution, as well as provide validation of plasticity models for materials that exhibit deformation twinning.




79.    Henry, S., G.-U. Gruen, et al. (2004). "Influence of Convection on Feathery Grain Formation in Aluminum Alloys." Metallurgical and Materials Transactions A 35A(No. 8): 2495-2501.

The influence of convection on the formation of feathery grains, i.e. of columnar grains made of twin dendrites growing along <110> directions, in AA1050 aluminum alloys has been studied. Round billets have been semicontinuously cast in a mold equipped with lateral liquid feeding. The fluid flow pattern in the liquid sump has been modeled using Fidap software. Feathery grains have been observed in the region opposite the mold entrance, i.e., in the regions where the change of the velocity field (shearing rate) is the highest. Electron backscattered diffraction (EBSD) maps of two feathery regions, which were symmetric with respect to the liquid flow pattern, showed clear symmetry relationships. Furthermore, the <110> secondary dendrite arms had grown in directions opposite to the fluid flow. This experimental evidence brings more experimental support to the mechanism of feathery grain formation proposed earlier by Henry et al.




80.    Henry, S., P. Jarry, et al. (1997). "Electron Backscattered Investigation of the Texture of Feathery Crystals in Aluminum Alloys." Metallurgical and Materials Transactions A 28A(1): 207-213.

Scanning electron micrscopy (SEM), metallographic observations, and automated electron backscattered diffraction (EBSD) experiments were carried out on "feathery crystals" of a unidirectionally solidified (1D) Al-Cu alloy of a direct-chill (DC) cast Al-Mg-Si alloy. The results clearly show that the "feathery grains" are made of twinned lamallae, which are parallel to a (111) twin plane. The contrast seen in the metallographic sections after a Barker etching or observed in an SEM is perfectly corroborated with the EBSD reconstucted microstructure. The lamallae are separated by an alternance of straight and wavy lines. Some equiaxed lines are also observed occasionally in the specimens. From the <111> pole figures of the various grains, it is concluded that the thermal gradient direction is close to, but not necessarily within, the (111) twin plane: its direction is in between a [011] and [112] direction. Within a given feathery grain, small variantions of the crystallographic orientations (subgrain boundaries) are observed. The lamellae of one grain can sometimes penetrate into another one. Based upon this information, the mechanism of feathery grain growth previously proposed by Eady and Hogan is ruled out. Although no other growth mechanism is proposed yet, it is believed that feathery grains are the result of a competition similar to that occurring in normal dendritic alloys, but with twinned dendrites.




81.    Henry, S., T. Minghetti, et al. (1998). "Dendrite Growth Morphologies in Aluminum Alloys." Acta Materialia 46(18): 6431-6443.

Different aluminium alloys, in particular Al–Cu, Al–Mg and Al–Si, have been directionally solidified under well-controlled thermal and convection conditions. For relatively high solidification rates, particular growth morphologies were observed. The most common is linked with the formation of feathery grains: these are constituted by series of twinned lamellae, in which the dendrites have 110 trunks cut through by {111} twin planes. These grains undergo a selection mechanism which is similar to that occurring for regular 100 dendritic grains. The dendritic growth along 110 crystallographic directions is supposed to be due to a change in the anisotropy of certain properties of the alloy, such as the solid/liquid interfacial energy and/or the atom attachment kinetics. When solidification conditions become less favourable to 110 growth morphologies, a mixed dendritic form containing 110 trunks and 100 arms may be obtained. In the case of the 5182 Al–Mg type alloy, 110 columnar grains which were not twinned could be observed together with feathery crystals. The possibility of such changes in the growth direction of aluminium alloys was further demonstrated by the observation of dendrites of Al–Cu–Mg solidified in a Bridgman device. In this case, 112 dendrites grow and progressively change their growth direction, thus showing curved shapes




82.    Her, T. H., R. J. Finlay, et al. (2000). "Femtosecond Laser-Induced Formation of Spikes on Silicon." Applied Physics A 70(4): 383-385.




83.    Heripre, E., A. Roos, et al. (2005). "Experimental and numerical study of plastic behaviour and crack propagation in gamma-based TiAl microstructures." ONERA: Tire a Part 174.

This paper discusses a coupling between different experimental techniques such as Electron Back-Scattering Diffraction (EBSD), micro-extensometry and Atomic Force microscopy, with numerical Finite Element studies. This coupling can be used to study plasticity and fracture by taking into account the influence of microstructure. By minimising the difference between numerical and experimental results both at the microscopic and macroscopic scales, the optimum parameters of the constitutive law can be obtained.




84.    Herman, G., B. Lechevalier, et al. (2004). Microstructures of ferritic warm rolled plain carbon steels. Ultrafine Grained Materials III (as held at the 2003 TMS Annual Meeting), Charlotte, North Carolina, USA.

Little work has been performed on ferritic warm deformation of plain carbon steels. By contrast, work on ferritic stainless steels has shown that intense hot deformation could lead to a fully dynamically recrystallised structure. This suggests that warm deformation in the ferritic region of steels could also lead to such microstructure, and therefore interesting prospects for the improvement of properties through grain size refinement. That is why the present prospective work focuses on warm rolling of plain carbon steels. Low carbon microalloyed steels (C<0.1%, 0.5%<Mn<1.5%, Si<0.4% + V) were intensively warm rolled (400-700quiaxed r C) in the ferritic region after austenitic hot rolling on a laboratory rolling mill. This study shows that warm deformation in the ferritic region of plain carbon steels is indeed able to induce fragmentation of grains, although fragmentation remains partial. The EBSD analyses of microstructures suggest that in our case warm rolling induces continuous dynamic recrystallisation, although heterogeneous.




85.    Hernàndez, D., M. Diaz-Fuentes, et al. (2003). Study of Grain Boundary Ferrite Nucleation in V Microalloyed Steels by EBSD. Thermec' 2003, Leganés, Madrid, Spain, Trans Tech Publications Ltd.

The effect of small vanadium additions to low carbon steels on the orientation distribution of ferrite grains formed at prior austenite grain boundaries during transformation was examined. A comparison has been made with a similar transformation microstructure for a plain low carbon steel. The electron backscattered diffraction technique (EBSD) has been used to evaluate the deviation angle of ferrite from the K-S and N-W theoretical relationships. It has been observed that these relationships are weaker for the V microalloyed steel than for the plain carbon.




86.    Herwegh, M. and K. Kunze (2002). "The influence of nano-scale second-phase particles on deformation of fine grained calcite mylonites." Journal of Structural Geology 24: 1463-1478.

Gray and white carbonate mylonites were collected along thrust planes of the Helvetic Alps. They are characterized by very small grain sizes and non-random grain shape (SPO) and crystallographic preferred orientation (CPO). Presumably they deformed in the field of grain size sensitive flow by recrystallization accommodated intracrystalline deformation in combination with granular flow. Both mylonites show a similar mean grain size, but in the grey mylonites the grain size range is larger, the grain shapes are more elongate, and the dynamically recrystallized calcite grains are more often twinned. Grey mylonites have an oblique CPO, while the CPO in white mylonites is symmetric with respect to the shear plane. Combustion analyses and TEM investigations revealed that grey mylonites contain a higher amount of highly structured kerogens with particle sizes of a few tens of nanometers, which are finely dispersed at the grain boundaries. During deformation of the rock, nano-scale particles reduced the migration velocity of grain boundaries by Zener drag resulting in slower recrystallization rates of the calcite aggregate. In the grey mylonites, more strain increments were accommodated by individual grains before they became refreshed by dynamic recrystallization than in white mylonites, where grain boundary migration was less hindered and recrystallization factors were faster. Consequently, grey mylonites represent 'deformation' microfabrics while white mylonites are characterized by 'recrystallization' microfabrics. Field geologists must utilize this different deformation behavior when applying the obliquity in CPO and SPO of the respective mylonites as reliable shear sense indicators. Copyright 2002 Elsevier Science Ltd. All rights reserved.




87.    Higginson, R. L. (2004). The Effect of Strain Path on the Recrystallisation of an Aluminium Manganese Alloy. Second Joint International Conference on Recrystallization and Grain Growth, ReX & GG2, SF2M, Annecy, France, Trans Tech Publications Ltd.

The strain path undergone by a material can have a significant influence on the deformation behaviour, recrystallisation kinetics, grain size and crystallographic texture. To study the influence of strain path, studies of an aluminum-1%manganese alloy have been subjected to a number of strain path changes. These have been achieved using combinations of plane strain and free compression to give strain paths of 0, 90 and 180°. The development of the dislocation substructure resulting from each stage of deformation was studied using Electron Back Scatter Diffraction (EBSD) and Transmission Electron Microscopy (TEM). Following deformation annealing was carried out to determine the effects of the strain path changes on the recrystallisation kinetics and grain size. Results have shown that the strain path angles cannot be used to satisfactorily describe the material behaviour when mixtures of deformation modes are used.




88.    Higginson, R. L. and G. D. West (2005). The Study of Texture Development of High Temperature Oxide Scales on Steel Substrates using Electron BackScatter Diffraction. Textures of Materials - ICOTOM 14, Leuven, Belgium, Trans Tech Publications.

Low silicon carbon steel has been oxidised at varying temperatures in free flowing air using a thermomechanical simulator to control heating and cooling rates. The resultant oxide scales have been studies using Electron Backscatter Diffraction (EBSD) and the phases identified by the differences in the diffraction patterns. The crystallographic textures were calculated from the EBSD data. There is a correlation between the textures of the different phase layers within the scale, which depends on the formation mechanism of the individual phases.




89.    Higginson, R. L., B. Roebuck, et al. (2002). "Texture development in oxide scales on steel substrates." Scripta Materialia 47(5): 337-342.

Oxide scale growth and microstructures on steels are complex and depend on a large number of variables e.g. temperature, time, atmosphere and alloying elements. The current study has illustrated that there is a complex crystallographic relationship between the scale layers, which also depends on these parameters.




90.    Hirose, A., D. Nakamura, et al. (2003). Microstructure and Mechanical Property of Laser Welds of Single Crystal Nickel Base Superalloy CMSX-4. Thermec' 2003, Leganés, Madrid, Spain, Trans Tech Publications Ltd.

In the present work, 2mm thick plates of a single crystal nickel base superalloy, CMSX-4, were welded using a CO2 laser. The effects of the welding direction deviating from the base metal <100> direction on the microstructure of the weld fusion zones were investigated. In bead-on welding, while the welds with deviation angles of 15 degrees or more showed fusion zone transverse cracks, those with deviation angles within 5 degrees had no cracks and the solidification grains grew epitaxially from the base metal grains except for the bead neck regions, which contained some stray crystals. As deviation angles increased, the number of the stray crystals increased. As a result, the major part of the fusion zones can be the single crystal having the same crystal orientation as the base metal when deviation angles are within 5 degrees. The butt welds with the declinations of the crystal orientation of the two base metals up to 10 degrees had no cracks. The bead-on weld and the butt weld joints having no cracks were more than 800MPa, which is almost 80% of that of the base metal, in tensile strength at 1123K.




91.    Hirose, Y., M. Fujisawa, et al. (2004). Crystal Structure Characterization of Copper Interconnects in USLIs Using Electron Backscatter Diffraction Pattern (EBSP) Technique. Proceedings of the 8th Asia-Pacific Conference on Electron Microscopy (8APEM). N. Tanaka, Y. Takano, H. Moriet al. Ishikawa, Japan, 8APEM Publication Committee: 442-443.

We applied the EBSD technique to the examination of Cu interconnects in ULSIs, and in particular, the line-width dependence of the crystal microstructure was investigated. It is revealed that grain sizes rapidly become smaller and crystal grains with a bamboo structure are dominant when the line-width is less them 2 µm. With regard to orientations, there is a tendency that [111] orientation is strong for all line-widths, while various crystal planes appear with narrowing of the line-width. Furthermore, we predict the reliabilities of all interconnects by analyzing the quantitative and statistical distribution of what's in the area with a non-bamboo grain structure.




92.    Hirose, Y., N. Hashikawa, et al. (2004). "Microsampling technique for EBSP inspection on the cross-sections of copper trench lines in ULSIs." Journal of Electron Microscopy 53(5): 567-570.

The crystal microstructure of copper interconnects in ultra large scale integrations (ULSIs), depends on factors such as the trench line width and patterns. Therefore, inner crystal characterisation of the desired trench lines composed of copper is required. Electron backscatter diffraction pattern (EBSP) inspection has become a powerful technique for analysing the crystal characterisation of interconnects. However, EBSP inspection is sensitive to surface conditions such as contamination and strain. In this study, we applied the focused ion beam (FIB) technology, particularly, the microsampling technique to the preparation of samples for EBSP inspection on the cross-sections of the copper trench lines. As a result, we demonstrate that a damaged layer composed of a crystalline substance is formed on the plane of the copper as revealed by the 30 kV Ga+ FIB milling, but an EBSP signal is detectable. In conclusion, the cross-sectional sample preparation technique employing microsampling is found to be very powerful for analysing the inner crystal characteristics of the desired copper trench lines by EBSP inspection.




93.    Hirota, T., K.-I. Ikeda, et al. (2005). "Low-temperature fabrication of polycrystalline Si thin film using Al-induced crystallization without native Al oxide at amorphous Si/Al interface." Japanese Journal of Applied Physics Part 1 44(7A): 4770-4775.

Low-temperature fabrication of polycrystalline silicon (poly-Si) thin film has been performed by Al-induced crystallization (AIC), and the structural properties have been investigated. In our experiments, to prevent native oxidation of Al film, an amorphous silicon (a-Si)/Al bilayer was formed on the SiO2/Si substrate by electron beam evaporation without breaking the vacuum. The a-Si/Al/SiO2/Si structure was then heated at a low temperature of 400 A for bo C to induce AIC. It was confirmed that layer exchange of the a-Si/Al bilayer is induced even though there is no native oxidation of Al film, which was demonstrated by scanning transmission electron microscopy and energy dispersive X-ray analysis. The mechanism for layer exchange of the a-Si/Al bilayer has been discussed. Furthermore, it was verified by scanning electron microscopy and spectroscopic ellipsometry that the a-Si/Al thickness ratio of roughly 1: 1 is suitable to achieve a flat surface morphology of poly-Si. In addition, it was found, by X-ray diffraction and orientation imaging microscopy, that the Si(111)-oriented grain becomes dominant with decreasing thickness of the a-Si/Al bilayer.




94.    Hirsch, P. B. and C. J. Humphreys (1970). The Dynamical Theory of Scanning Electron Microscope Channeling Patterns. Scanning Electron Microscopy, ITT Research Institute.




95.    Hirth, S. and G. Gottstein (1996). Microtexture of Discontinuous Precipitationin an Al-2.8at%Ag-Ga Alloy. Eleventh International Conference on Textures of Materials, Xi'an, China, International Academic Publishers.




96.    Hjelen, J., A. H. Qvale, et al. (1994). "Electronmicrodiffraction (EBSP) in the scanning electron microscope (SEM): Further hardware development to improve pattern quality." Materials Science Forum 157-6(pt 1): 137-142.

Most EBSP hardwares today contain very light sensitive TV tube cameras. This paper describes a new EBSP hardware where a high resolution CCD camera is applied to obtain high resolution images of diffraction patterns. As a result, EBSP from aluminum showing higher order diffractions lines is presented. The CCD camera provides several advantages regarding picture quality. Grain orientation measurements, based on EBSPs acquired with a CCD camera, will be more accurate. This is due to the fact that there is no geometric distortion in EBSPs acquired with a CCD camera. The hardware construction, together with an appropriate positioning of the CCD camera, allows accurate calibration opportunities. When the EBSP solid angle is changed there is no need for any mechanical refocusing of the CCD camera. Due to the small size of the compact CCD camera, it is easy to interface the EBSP hardware to a SEM port. (Author abstract) [References: 10]




97.    Hjelen, J., H. Weiland, et al. (1990). The Orientation Distribution in Channel Die Compressed Al Single Crystals as Studied by Microdiffraction Techniques in SEM and TEM. Ninth International Conference on Textures of Materials (ICOTOM 9), Avignon, France, Gordon and Breach Science Publishers.




98.    Hjelen, J., R. Orsund, et al. (1993). "EBSP, Progress in Technique and Applications." Textures and Microstructures 20: 29-40.




99.    Ho, H. M., W. Lam, et al. (2003). "Direct gold and copper wires bonding on copper." Microelectronics Reliability 43: 913-923.

The key to bonding to copper die is to ensure bond pad cleanliness and minimum oxidation during wire bonding process. This has been achieved by applying a organic coating layer to protect the copper bond pad from oxidation. During the wire bonding process, the organic coating layer is removed and a metal to metal weld is formed. This organic layer is a self- assembled monolayer. Both gold and copper wires have been wire-bonded successfully to the copper die even without prior plasma cleaning. The ball diameter for both wires are 60 lm on a 100 lm fine pitch bond pad. The effectiveness of the protection of the organic coating layer starts from the wafer dicing process up to the wire bonding process and is able to protect the bond pad for an extended period after the first round of wire bond process. In this study, oxidization of copper bond pad at different packaging processing stages, dicing and die attach curing, have been explored. The ball shear strength for both gold and copper ball bonds achieved are 5 and 6 g/mil2 respectively. When subjected to high temperature storage test at 150 °C, the ball bonds formed by both gold and copper wire bond on the organic coated copper bondpad are thermally stable in ball shear strength up to a period of 1440 h. The encapsulated daisy chain test vehicle with both gold and copper wires bonding have passed 1000 cycles of thermal cycling test (-65 to 150 °C). It has been demonstrated that orientation imaging microscopy technique is able to detect early levels of oxidation on the copper bond pad. This is extremely important in characterization of the bondability of the copper bond pad surface.




100.    Hobbs, S. Y. (1982). "Miniature Pneumatic Tensile Stage for Scanning Electron-Microscopes." Review of Scientific Instruments 53(7): 1097-1098.




101.    Hoel, R. H. and D. J. Dingley (1982). "Precision Tensile Testing of Small Specimens of Polysulfur Nitride in the Scanning Electron-Microscope." Journal of Materials Science 17(10): 2990-2996.




102.    Hoffmann, A., U. Martin, et al. (2006). "Hardening mechanisms and recrystallization behaviour of several molybdenum alloys." International Journal of Refractory Metals and Hard Materials 24(4): 298-305.

The present study describes the effect of thermomechanical treatments on the microstructure of molybdenum-titanium and the molybdenum alloy TZM (0.5 wt.% Ti, 0.08 wt.% Zr). These alloys were processed by a powder metallurgical route including extensive rolling at temperatures above 1200 by analy C achieving deformation degrees of 2.87 (logarithmic). The alloys exhibit a distinct increase in yield stress without decreasing elongation at fracture. To study the recrystallization behaviour, several samples were annealed at temperatures between 1100 he recrys C and 1600 temperatu C for 15 min until 6 h. The microstructure was examined by scanning electron microscopy (SEM), electron backscattering diffraction (EBSD) and transmission electron microscopy (TEM). Strain rate controlled tensile tests and Vickers hardness measurements are used to determine the mechanical properties. In both alloys a distinct substructure containing subgrains is formed during deformation. A kind of (sub)grain refinement was considered to be responsible for hardening. Present particles are able to raise the recrystallization temperature and thus sustain the grain size effects even at working temperatures above 1200 f elevate C.




103.    Hogg, S. C. and H. V. Atkinson (2005). "Inhibited Coarsening of a Spray-Formed and Extruded Hypereutectic Aluminum-Silicon Alloy in the Semisolid State." Metallurgical and Materials Transactions A 36A(1): 149-160.

The microstructural evolution of a spray-formed and extruded hypereutectic aluminum-30 pct silicon-5 pct copper-2 pct magnesium alloy heated into the semisolid state has been investigated. Liquid is formed initially by a quaternary eutectic reaction and then by a ternary melt reaction. These reactions occur relatively quickly. However, the binary Al-Si eutectic melt reaction takes a significant time—around several hours depending on the temperature. The coarsening rate constants (K) for the growth of the silicon particles are approximately three to four orders of magnitude lower than those for the majority of metal spray-formed alloys. This may be associated with difficulties in addition or removal of atoms from the low index silicon facets. Where growth does occur, agglomeration of silicon particles may play a large role, especially at higher liquid contents. Electron backscatter diffraction (EBSD) gives evidence of agglomeration, and furthermore shows that high-angle silicon-silicon boundaries are not wetted with liquid.




104.    Hogg, S. C., A. Lambourne, et al. (2006). "Microstructural characterisation of spray formed Si–30Al for thermal management applications." Scripta Materialia 55(1): 111-114.

This paper presents a study of the microstructure of a spray formed Si–30 wt.%Al alloy used in electronic packaging applications. The microstructure consisted of 5 μm equiaxed primary Si grains and a coarse grained Al-rich phase with occasional regions of 10 μm equiaxed Al-rich grains interpenetrating the Si network with no evidence of a lamellar Al–Si eutectic. This unusual microstructure arose because of the particular solidification conditions during and immediately after the spray forming process and the large alloy freezing range.




105.    Hogg, S. C., I. G. Palmer, et al. (2005). Control of Microstructure in a Spraycast Al-Mg-Li-Zr Alloy. 9th International Conference on Aluminium Alloys, Brisbane, Australia, Institute of Metals and Materials Australasia Ltd.

This paper describes the microstructural investigation of an Al-5.31Mg-1.15Li-0.28Zr alloy produced by spraycasting. Following a dispersoid precipitation treatment of 4h at 400 deg C, cylindrical samples were hot compressed to a range of total strains and a range of strain rates at temperatures between 250-400 deg C. Electron backscattered diffraction showed a strong dependence of grain size on compression temperature with new grains nucleating at regions of microscopic strain localisation such as triple points and grain boundaries. There was an inverse relationship between the size of these new grains and the Zener Holloman factor during compression. The microstructures from the small scale compression experiments have been compared with those of larger scale forgings, and indicated that under similar conditions, microstructural evolution was broadly similar.




106.    Holesinger, T. G., P. N. Arendt, et al. (2005). "Liquid mediated growth and the bimodal microstructure of YBa2Cu3O7δ films made by the ex situ conversion of physical vapor deposited BaF2 precursors." Journal of Materials Research 20(5): 1216-1233.

YBa2Cu3Oy (YBCO) films produced by the ex situ conversion of BaF2-based precursors deposited by physical vapor deposition on ion-beam assisted deposited (IBAD) yttrium-stabilized zirconia (YSZ) and rolling-assisted biaxially textured substrates (RABiTS) templates are characterized by a bi-axially aligned, laminar grain structure that results from the anisotropic growth characteristics of the YBCO phase and its precipitation from a transient liquid phase during the conversion process. A bimodal microstructure characterizes these films and is defined by large, well-formed YBCO grains with Y2O3 precipitates in the bottom region of the film and small YBCO grains with a high density of stacking faults in the upper half. Ba2Cu3Oy or Ba-O-F/CuO second phase layers were often found between large YBCO grains in the bottom half of the films. YBCO grain sizes exceeded 50 μm within the plane of the film in some cases. Conversely, discrete secondary phases of Y2Cu2O5, Y2O3, and Ba2Cu3Oy/Ba-O-F could be found among the much smaller YBCO grains in the top portion of the bimodal structure. The dividing line of the bimodal structure was generally at one half of the film thickness, although exceptions to this trend were found. The highest critical current densities (Jc) and best film alignments for a given film thickness were found in samples where the layers of Ba2Cu3Oyor Ba-O-F were minimized or eliminated from the films. Samples quenched after partial conversion show the segregation of CuO to the top region of the film and the lateral growth of large YBCO grains from a precursor mix of Y2Cu2O5and Ba-O-F. The data demonstrate that transient liquid phases are part of the conversion process of BaF2-based YBCO films. The control of both CuO segregation and the amount of liquid phases generated during the initial stages of phase formation is needed for optimizing the ex situ conversion process for high-Jc coated conductors.




107.    Hollinshead, P. A. (1996). Crystallographic Texture in Cold Rolled 5182 and its Change in the Panel Wall due to Shell Formation. Aluminum Alloys for Packaging II. J. G. Morris, S. K. Das and H. S. Goorich, The Minerals, Metals and Materials Society: 117-127.




108.    Hollinshead, P. A. (1996). The Evolution of Crystallographic Texture during the Recrystallization of Hot Rolled 5182. Aluminum Alloys for Packaging II. J. G. Morris, S. K. Das and H. S. Goorich, The Minerals, Metals and Materials Society: 27-39.




109.    Holt, D. B. (2000). "The Remote Electron-Beam-Induced Current Analysis of Grain-Boundaries in Semiconducting and Semi-insulating Materials." Scanning 22(1): 28-51.




110.    Holt, D. B., B. Raza, et al. (1996). "EBIC studies of grain boundaries." Materials Science and Engineering B 42(1-3): 14-23.

REBIC is a powerful technique for the study of defects, especially grain boundaries (GBs), in ill developed, high-resistivity (semi-insulating) materials. Ideas for modelling GB REBIC contrast have been proposed but neither quantitatively developed nor applied to details of experimental contrast. The model of two Schottky barriers back to back for charged boundary (peak and trough) contrast and the high-resistivity boundary layer model for terraced contrast are spelled out in further detail here. They are then applied to observations on high-resistivity polycrystalline ZnSe. The models suffice to account for most features observed. The relative doping density on either side of boundaries can be determined by measuring the barrier width as a function of the reverse bias. The sign of the charge on boundaries can be deduced by observing whether the peak or trough occurs on the dark terrace side of a boundary. Observations of the reversal of peak and trough contrast along the length of boundaries indicate that both minus vely and plus vely charged regions occur. The asymmetry of the peaks and troughs at many terraced boundaries can be accounted for by the biasing of the Schottky barriers by the voltage drop across the barrier layer due to the REBIC current. The significance of the additional information obtainable by (i) the crystallographic characterization of boundaries by the EBSP technique and (ii) studies of the temperature dependence of REBIC contrast is discussed. (Author abstract) [References: 17]




111.    Holt, R. A. and P. Zhao (2004). "Micro-texture of extruded Zr–2.5Nb tubes." Journal of Nuclear Materials 335(3): 520-528.

We report the micro-texture of two extruded Zr–2.5Nb tubes determined using scanning electron microscopy combined with electron back-scattering diffraction (SEM/EBSD) and transmission electron microscopy and selected area diffraction (TEM/SAD). The pole figures determined by SEM/EBSD correspond well with bulk pole figures previously determined by X-ray diffraction (XRD). Three components of texture are seen to correlate with the shape and morphology of theα-grains and their contained dislocation substructures. The first component corresponds to elongated alpha grains containing a high density of a and c + a dislocations in which the c-axis is oriented at a relatively high angle to the long dimension of the α-grains as viewed in transverse section; these grains comprise a texture component with the c-axes in the radial transverse plane, tilted towards the radial direction. The second component corresponds to elongated α-grains containing a low dislocation density in which the c-axis is oriented parallel to the long dimension of the alpha grains: these grains also comprise a texture component with the c-axis in the radial/transverse plane, but predominantly in the transverse direction. The final component corresponds to colonies of Widmanstätten-like α-grains that are transformed from the ß-phase: the majority of these grains have their c-axes in the axial direction. These grain have very low dislocation densities and are probably developed during cooling, after extrusion.




112.    Holzapfel, B., L. Fernandez, et al. (2001). "Grain Boundary Networks in Y123 Coated Conductors: Formation, Properties and Simulation." IEEE Transactions On Applied Superconductivity 11(1): 3872-3875.




113.    Home, E. R., J. A. Basinge, et al. (2005). Variance of the Grain Boundary Character Distribution. Textures of Materials - ICOTOM 14, Leuven, Belgium, Trans Tech Publications.

A method for estimating the variance of the grain boundary character distribution from experimental recovery of the two-point correlation functions is derived. The method is illustrated in 2-D to analyze the variance of “susceptible” boundaries in alloy 304 stainless steel. Comparison of these estimates with results obtained directly from OIM measurements is presented.




114.    Homer, E. R., B. L. Adams, et al. (2006). "Recovery of the grain boundary character distribution through oblique double-sectioning." Scripta Materialia 54(6): 1017-1021.

A method for the retrieval of the complete grain boundary character distribution by oblique double-sectioning is proposed. The method, which is similar to the recovery of the orientation distribution from sets of incomplete pole-figures, is efficient and provides many advantages as compared to calibrated serial sectioning. As compared to standard stereological approaches, the new methodology retains the advantage of direct measurement of the grain boundary inclination parameters. Solutions to the fundamental equation of oblique double-sectioning are provided in the Fourier space, and some specifics in sample preparation are introduced.




115.    Homma, H. and B. Hutchinson (2003). "Orientation dependence of secondary recrystallisation in silicon–iron." Acta Materialia 51: 3795-3805.

Experiments and analyses have been carried out to reach a better understanding of the mechanism of Goss texture formation during the secondary recrystallisation of silicon steel processed by the single cold reduction route. A new experimental approach demonstrated the effect of misorientation on the growth rates of secondary grains and it is shown that these rates are controlled by the proportion of matrix grains having Σ9 CSL relationships to growing secondary grains. It is considered that the Σ9 boundaries have lower energy than general grain boundaries and so are less strongly inhibited by Zener drag. The relative infrequency of Σ9 boundaries around the periphery of secondary grains is seen as evidence for their sacrificial behaviour. Other experiments involving growth of randomly oriented nuclei provide independent support for the important role of Σ9 boundaries during secondary recrystallisation in this steel.




116.    Homma, H., N. Yoshinaga, et al. (2001). "Micro-scale Orientation Study on RD//<011> Cold Rolling Texture and Recrystallisation in Steel." Materia Japan 40(7): 650-654.




117.    Homma, H., N. Yoshinaga, et al. (2002). Micro-Scale Orientation Study on RD//<011> Cold Rolling Texture in Steel. ICOTOM 13, Seoul, Korea, Trans Tech Publications Inc.

Heavily cold rolled iron was examined with the EBSP-OIM system installed on the finely developed high resolution scanning electron microscope in the present work. Alpha fiber or <011>//RD structures were successfully observed demonstrating the crystallographic construction of heavily strained substructures at the interiors of the grains. The series of alpha fiber, i.e. {100}<011> - {211}<011> - {111}<011>, is recognised as smoothly deformed structures achieved with the dual-slips of {211}<111>, {110}<111>, etc. during the cold rolling. Taylor factor analysis tells the necessary amount of the slip for each orientation in alpha fiber, as {100}<011> is the lightest and {111}<)11> is heavier. When Taylor deformation is hard, non-Taylor deformations may be easily introduced, such as the slips with specific single systems which ought to be appearing as band structures where the strain is locally concentrated at the grain interior. The present study observed {211}<111> preferential slip creating heterogeneously deformed band structures in 90% cold rolled iron. The slip variants seemed to be selected for having the highest Schmid factor, therefore the active slip systems changed depending on the orientation of each alpha fiber grain. For example, near-{100}<011> grains possess a mono band structure, on the other hand crossing dual band structures were observed in near-{111}<011> grains, which might be attributed to so called fish-born-structure, resulting in highly strained structure.




118.    Homma, H., S. Nakamura, et al. (2004). On {h,1,1}<1/h,1,2>, the Recrystallisation Texture of Heavily Cold Rolled BCC Steel. Second Joint International Conference on Recrystallization and Grain Growth, ReX & GG2, SF2M, Annecy, France, Trans Tech Publications Ltd.

Heavily cold rolled BBC steel has been indicated to generate {411}<148> recrystallisation texture and its family orientations which might be represented as {h,1,1}<1/h,1,2>. As a-fibre structure, or RD//<011> texture, is significantly developed during cold rolling, it is naturally speculated to be the recrystallisation site of {h,1,1}<1/h,1,2> fibre. The present paper prompts to demonstrate the recrystallisation procedure by utilising EBSP-OIM analysis. The first demonstration was carried out with OIM analysis on partially recrystallised cold rolled steel. At the stage of 50% recrystallisation, only ND//<11> texture has appeared for the recrystallised area. {100}<011> - {211}<011> α-fibre remains as deformed structure, and several {h,1,1}<1/h,1,2> grains could be found at the grain boundaries. Therefore, a bicrystal of {100}<011> was employed to simulate the irregular deformation at the grain boundary. After cold rolling, a warp toward the grain boundary was observed. Although the interior of the {100}<011> single crystal was hardly recrystallised, sharp {411}<148> texture was created along the grain boundary. In order to confirm the phenomenon, another experiment was carried out that a cold rolled {100}<011> single crystal was bent along the rolling direction and annealed. Very sharp {411}<148> recrystallisation texture was formed again at the bent perimeter. These experimental results lead us to conclude that the irregular strain was sufficiently piled at the grain boundary after the heavy deformation and generates {h,1,1}<1/h,1,2> texture. On {100} pole figures, the recrystallisation textures were equivalently scattered around three <100> poles, therefore the rotation relationship around <111> axes with the original orientation was suggested.




119.    Hong, B. D. and K. S. Han (2002). Effect of Inter-Pass Aging on Recrystallization Texture in 3% Si Grain-Oriented Electrical Steels. ICOTOM 13, Seoul, Korea, Trans Tech Publications Inc.

Aging treatment during cold rolling passes is effective in improving magnetic properties of 3% Si grain oriented electrical steels. The effect of interpass aging treatment during cold rolling on the recrystallization texture is associated with the interaction between deformation of cold rolling and interstitial elements like carbon and nitrogen. Aging treatment during interpasses of cold rolling stage increases the dislocation density and makes the tangled dislocation structure. The present work aims at investigating the texture change by aging treatment in the primary and secondary recrystallization. The main primary texture changes are the slight increase of{110}<001> and decrease of {111}<112> and {210}<001> with the increase of aging temperature. This results in the decrease of final grain size of secondary recrystallization. Pass aging at 150~250°C for 10 minutes improves also significantly the magnetic flux density in the low carbon grain oriented electrical steels.




120.    Hong, H. U., B. S. Rho, et al. (2001). "Correlation of the M23C6 precipitation morphology with grain boundary characteristics in austenitic stainless steel." Materials Science and Engineering A318(1-2): 285-292.

The relationship between grain boundary characteristics and the formation of grain boundary carbides in AISI 304 stainless steel have been investigated by using the electron backscattered diffraction (EBSD) technique. It was observed that an increase in the misorientation between two adjacent grains resulted in a change in the carbide morphology from a plate-like to an acute triangular form, where carbides preferentially maintained coherency with the grain for which the {111} planes made the smallest angle with the grain boundary plane. The carbides grew into the other grain at a later stage, having the lowest interfacial energy, which subsequently resulted in the triangular carbide morphology. After low cycle fatigue with a hold time at tensile peak strains, it was observed that cavity formation was more pronounced at random boundaries than at coincidence site lattice (CSL) boundaries. This result provides a good explanation that acute triangular carbides, which predominantly precipitate at random boundaries, are more likely to lead to cavity nucleation than the plate-like carbides precipitate at CSL boundaries.




121.    Hong, M.-H., S.-H. Choi, et al. (2002). Influence of Substrate Texture on the Galvannealed Coating by EBSD. ICOTOM 13, Seoul, Korea, Trans Tech Publications Inc.

Interstitial free steels produced by the addition if Ti and/or Nb to precipitate interstitial carbon and nitrogen atoms are galvannealed for automobile panels in the respects of their good corrosion resistance, weldability, and paintability. An understanding of the phase evolution that takes place at the interface between liquid zinc and substrate steel is essential to obtain good quality of galvannealed coating. The microstructure of coating depends on the substrate composition, grain size, texture, and galvanizing conditions. In the present study, high strength interstitial free sheet steels containing Mn and P were galvannealed in an industrial CGL. The effect of strength hardening elements on the substrate texture as well as microstructural evolution of the zinc coating has been investigated by optical microscopy, scanning electron microscopy, transmission electron microscopy and electron backscattering diffraction techniques.




122.    Hong, S. C., S. H. Lim, et al. (2003). "Effects of Nb on strain induced ferrite transformation in C-Mn steel." Materials Science and Engineering A 355: 241-248.

Effects of the Nb addition on the strain induced ferrite transformation just above Ar3 temperature were investigated. Hot compression tests were performed with varying the true strain up to 1.6 (80% reduction) using Gleeble 1500. After the hot deformation, samples were immediately water-quenched to examine ferrite formation characteristics. The grain boundary misorientation angles were measured by electron backscatter diffraction in order to observe evolution of the ferrite grains. For reheating temperatures such as 900 and 1000 °C, where Nb was mostly precipitated as NbC, strain induced ferrite grains of 1-2 µm were formed homogeneously within the austenite grain in Nb steel. In the cases of higher reheating temperatures 1100 and 1250 °C, where most of Nb was dissolved, the strain induced ferrite transformation was remarkably reduced and the ferrite morphology was changed to elongated grains. It was considered that the ferrite transformation during deformation was retarded by both the solute drag effect of Nb and the consumption of strain energy for the dynamic precipitation of NbC.




123.    Hong, S.-H. and D. N. Lee (2002). Effect of Temper Rolling on Grain Growth in IF Steel. ICOTOM 13, Seoul, Korea, Trans Tech Publications Inc.

A study has been made of the effects of temper rolling on the grain growth in strain annealing of IF steel sheet. A 92.5% cold rolled and annealed IF steel sheet was temper rolled by 0.4%, 0.8% and 1.2% and subsequently annealed at 670°C for various time periods. The grains started to grow abnormally underneath the surface and grew into the center during strain annealing after 0.4% temper rolling. However, the grains did not grow after temper rolling by 0.8% and 1.2%. The pole figure and EBSD mesurements showed that the abnormally grown grains of 0.4% temper rolled IF steel sheet did not have any special orientation relationship with the primary recrystallization texture. A major grain growth mechanism was regarded to be the strain induced grain boundary migration rather than the grain boundary characteristics.




124.    Hong, S.-H. and D. N. Lee (2003). "The evolution of the cube recrystallization texture in cold rolled copper sheets." Materials Science and Engineering A 351(1-2): 133-147.

The S{123}<634> deformation texture has often been addressed to be responsible for the cube {001}<100> recrystallization texture in fcc metals from approx =40 deg <111> rotational relation. After the 95% cold rolled copper sample was heated up to various temperatures at the rate of 2.5 K s-1 and quenched, the density of the S component was slightly lowered while that of the copper component {112}<111> was decreased drastically. This result suggests indirectly that the decrease in the density of the copper component is closely linked to the increase in the cube component. Electron backscatter diffraction (EBSD) studies also indicated that the cube recrystallization texture was linked with the {112}<111> deformation texture. The results have been discussed based on the strain energy release maximization (SERM) model, in which the recrystallization texture is determined so that release of the strain energy due to dislocations can be maximized during annealing.




125.    Hong, S.-H. and D. N. Lee (2003). "Grain coarsening in IF steel during strain annealing." Materials Science and Engineering A 357(1-2): 75-85.

A study has been made of the grain growth in IF steel during strain annealing. A 92.5% cold rolled and annealed IF steel sheet was temper rolled by 0.4% and subsequently annealed at 750, 850, and 950 deg C for various time periods. The grains started to grow abnormally near the surface and grew into the center during strain annealing. The pole figure and EBSD measurements showed that the abnormally grown grains did not have any orientation relation with the primary recrystallization texture. The calculated Taylor factors indicate that grains which underwent less deformation during temper rolling due to their orientations grow at the expense of surrounding grains. A major grain growth mechanism was regarded to be the strain induced grain boundary migration rather than grain boundary characteristics.




126.    Hong, S.-H., B. M. Lim, et al. (2002). Texture and Corrosion Mechanisms in Aluminized Steel Sheet. ICOTOM 13, Seoul, Korea, Trans Tech Publications Inc.

Texture changes of aluminized coatings on steel sheet having Cr ranging from 0.0% to 1.0% in the coated layer were investigated, and corosion mechanisms of aluminized coatings with the Cr content change in the coating layer were deduced. The aluminized coating layer without Cr consisted of two phases. The surface layer was Al and the interfacial layer between the steel substrate and the coating layer was Al5Fe2. The aluminized coating layer containing 1.0% Cr consisted of three phases. The surface layer was Al, the middle layer was Al13Cr2, and the interfacial layer was Al13Fe4and Al5Fe2. The texture of the aluminized coating without Cr was characterized as a {001} fiber texture. As the Cr content in the aluminized layer was increased to 1.0%, the texture of the aluminized coating was not cahnged but the intensity of the {001) fiber texture was increased. The major orientation in the [Macro error: Can’t compile this script because “\” is an illegal character.] fiber texture was changed from the rotated cube orientation of the 0.1% Cr contained aluminized coating to the cube orientation of the 1.0% Cr contained aluminized coating. The polarization curve indicates that the corrosion resistance was increased as the Cr content n the aluminized layer was increased. For the aluminized coating without Cr, a porosity in the aluminum oxide film on the surface layer leads to preferential corrosion. After the aluminized coating layer was completely removed, the Al5Fe2 layer was selectively corroded and then the steel substrate was exposed to the electrolyte. The corrosion resistance of the aluminized coating without Cr depends on the thickness of the aluminum layer of the aluminized coating. For the aluminized coating with 1.0% Cr, the corrosion mechanism was different. After the aluminum layer was removed, the Al13Cr2 layer, which was known to be high corrosion resistant intermetallic compound, became a barrier against further corrosion. In this case corrosion was not continued even though the same current density at which the substrate was corroded in the aluminized coating without Cr was applied. The high corrosion resistance of the aluminzed coating containing 1.0% Cr was due to the texistence of the Al13Cr2 layer.




127.    Hong, S.-H., J. B. Kim, et al. (2002). The Role of Textures in the Corrosion Resistance of Electrogalvanized Zn Coatings. ICOTOM 13, Seoul, Korea, Trans Tech Publications Inc.

The generation of zinc coatings on steel sheet is one of the most commercially important processing techniques used to protect steel components exposed to corrosive environments. The coating properties are closely related to the microstructure of electrodeposits. One of the important factors that influence on the coating properties is texture. The texture of zinc coatings showed significant variations with the changes of the textures of steel sheets which were used as the substrates of zinc coatings. This study demonstrates a relationship between the corrosion behavior of the electrogalvanized zinc coatings and their textures as the texture changes of the substrates and the current density changes during electrodeposition. The texture of the zinc coatings on a fiber textured steel sheets was characterized by a {10·3} non fiber texture as a major component and a {00·2} fiber texture as a minor component. On the contrary, the texture of the zinc coatings on y fiber textured steel sheets was characterized by a mixture of the {00·2} fiber texture and the {10·3} fiber texture when deposited at low current density. The texture of the coating was gradually changed into a {10·3} pyramidal texture as a major component and a {00·2} fiber texture as a minor component as deposition current density increases. The coatings with a {00·2} texture have better corrosion resistance than those with a mixed texture of {10·3} and {00·2} components.




128.    Hong, S.-H., J. H. Choi, et al. (2000). Transformation from Rolling Texture to Recrystallization Texture in Copper. Thermec 2000, Las Vegas, Nevada, USA, Elsevier Science Ltd.

The {123}<634> deformation texture has often been addressed to be responsible for the {001}<100> recrystallization texture in fcc metals from ~40o<111> rotational relation. However, EBSD studies indicated that the {001}<100> texture arose from the {112}<111> deformation texture. The above result has been discussed based on the strain energy release maximization model, in which the direction of absolute maximum internal stress due to dislocations in the deformed matrix is parallel to the minimum Young’s modulus direction in recrystallized grains, whereby the energy release during recrystallization can be maximized.




129.    Hong, Y. C. L., C. J.; Yang, C. F. (2002). "The effects of alloying elements on the microstructures and mechanical properties in Mg-Al-X alloys." Chukung (Journal of Chinese Foundrymen's Association) 28(4): 18-27.

In this study alloying elements including Zn, Mn, Ti, Zr, Cr, Si, and a couple of rare earth metals were added to Mg-i wt. % Ai(Al) and Mg-3 wt. % Al (A3) alloys to form a variety of Mg-Ai-X ternary alloys. The influences of these alloying elements and the process variables of mechanical rolling on the microstructures and mechanical properties under strain rates of 1 x 10-2 approx1 x 10-4 s-1 at room temperature approx300 deg C were examined by using OM, SEM, EBSD, XRD, and tensile teser, etc. The results showed that a lamellar precipitate structure was observed in the hot rolled Al and A3 binary Mg-Al alloys. Additions of the third alloying elements including Zn, Mn, Ti, Zr and mischmetal tend to retard the formation of the lamellar structure. The results also revealed that a 1-step rolling process (95% hot rolling at 45O deg C) resulted in Mg alloy sheets with an average grain size about 20 mu m, while that a 2-step rolling process (50% hot rolling at 450 deg C +95% warm rolling at 250 deg C) refined the alloys to a grain size about l0 mu m. Characteristics of superplasticity were found in the fine grained Mg alloys, which were subjected to the 2-step rolling process. Among the Mg-Al-X alloys studied, the AZ31, AM3O and A3-0.l5Ti exhibited best formability and elongation about 150 approx180%. This value is better than those of other Mg-Al-X alloys under the optimal test conditions of 200approx250 deg C and strain rates of 1 x l0-3 approx1 x 10-4 s-1. EBSD study on the 2-step mechanical rolling processed A3-0.l5Ti alloy sheet revealed preferred orientation of {000l}, {211O} and {1O1O} plans on the rolling plane, side plane (parallel to the rolling direction) and transverse plane (perpendicular to the rolling direction), respectively. The texture sustained even after the Mg alloy sheet was annealed for on hour at 300 deg C.




130.    Hongbo, W., W. Sen, et al. (2004). "Preparation of highly-ordered carbon nanotube arrays in the anodized alumina template." Nuclear Techniques 27(9): 676-680.

A highly-ordered, hexagonally arranged alumina nanopore template was prepared by self-organized two-step anodization process of aluminum in oxalic acid solution. Highly parallel pores were obtained within domains of a few micrometers. Highly-ordered, parallel carbon nanotube arrays were successfully grown in the alumina template nanopores by chemical vapor deposition catalyzed by alumina itself. The nanotubes arrays are suitable for channeling of particle beams. The structures of aluminium, alumina template and carbon nanotubes were characterized by scanning electro microscopy (SEM) and electron back scattered diffraction (EBSD). The growth mechanism and formation condition of both alumina template and carbon nanotube were discussed.




131.    Hood, E., Y. Li, et al. (2005). Friction stir welding of TIMETAL 21S. 2006 TMS Annual Meeting, San Francisco, California, USA.

The β-titanium alloy, TIMETAL 21S, was welded by the Friction Stir Welding process. Good weldability was demonstrated for a range of welding parameters. Microhardness mapping indicates slight weld overmatching for the conditions studied. Transverse tensile properties for one welding condition were measured and found to be similar to the base metal properties. The microstructure of the weld zone was investigated by optical microscopy, scanning electron microscopy and by orientation imaging microscopy. Grain refinement was observed under all welding conditions and a post-weld torsion texture was found in all welds.




132.    Hooghan, T. K., P. Staib, et al. (2004). An Energy Filter for Electron Backscattering Diffraction. Microscopy and Microanalysis 2004, Savannah, Georgia, USA, Cambridge University Press.

Electron backscattering diffraction (EBSD) in the SEM is a commonly used technique for orientation or texture microscopy, and for point group determination. Backscattered electrons are produced when a stationary electron beam is focused on a highly tilted (~70o) specimen. The electrons that contribute to the Kikuchi pattern are those have not lost more than a few electron volts, and emerge from a smaller depth in the specimen than those reached by the primary beam. Commercially available EBSD systems use all the backscattered electrons generated by the incident beam to create Kikuchi patterns. Signal to noise ratio improvement is achieved by advanced image processing. Higher-order lines are usually lost in this process. Overall there is a loss of sharpness and dynamic range. Another problem is the measurement error associated with locating the edges and center of the Kikuchi band. The energy spread in the divergent electron source creates line broadening, which in turn reduces the accuracy of the measurements. Therefore it is expected to be possible to increase the contrast of EBSD patterns by energy resolved detection of the backscattered electrons [1]. The purpose of this work is to integrate an energy filter into an EBSD system. The aim is to increase the contrast in the pattern, to reduce the diffraction volume contributing to the pattern, and to improve our understanding of how to model the patterns. Backscattered electrons with energies well below the incident beam energy are thought to come from a larger volume of material and are expected only to blur the final unfiltered pattern because they cover a very wide range of wavelengths. A study by Monte Carlo methods, as might be expected, predicts that a higher spatial resolution should be achieved in EBSD when the patterns are energy filtered [2].




133.    Horikawa, K. and K. Yoshida (2005). Hydrogen Microprint with EBSP Analysis in Tensile-Deformed Al-5%Mg Alloy. 9th International Conference on Aluminium Alloys, Brisbane, Australia, Institute of Metals and Materials Australasia Ltd.

Hydrogen distribution in high-purity-based polycrystalline Al-5%Mg alloys was visualized by means of hydrogen microprint technique with electron backscattering pattern analysis after a tensile deformation at room temperature. The number of hydrogen atoms observed as silver particles on the slip lines was increased when the applied strain was increased. Hydrogen atom was observed at both slip lines and special grain boundaries when an airmelted specimen was deformed. It was shown that hydrogen atom accumulation at grain boundaries varied with the misorientation of grains and the angle to the tensile direction.




134.    Horn, H. R. (1987). "X-Ray Microscopy and X-Ray-Diffraction in Scanning Electron-Microscopy." European Journal of Cell Biology 44(S19): 26.




135.    Horn, H. R. F. (1984). "X-Ray Reflection-Topography in the SEM." Scanning 6(2): 69-74.




136.    Horn, H. R., E. P. Krautz, et al. (1987). "Investigation of Cold-Worked Surfaces of Single-Crystals of Tungsten by X-Ray-Diffraction and Se-Micrographs in the SEM." Zeitschrift fur Metallkunde 78(6): 417-420.




137.    Horstemeyer, M. F., J. A. Querin, et al. (2004). "Use of EBSD to quantify the microstructural damage in aluminum alloys under monotonic loading." JOM 56(11): 166.

A high degree of success has been achieved in the use of damage modeling for predicting the durability and reliability of cast components. Cast components typically have a high void volume fraction due to porosity. Under the stress triaxiality conditions present in thick walls, the porosity voids grow and coalease. Implementation of this damage modeling technique for predicting durability and reliability in rolled sheet components presents new challenges. Rather than damage accumulation originating at porosity voids,damage accumulation originates within shear bands in deformed aluminum sheet metal. The initial texture and evolving texture in sheet metal effects the shear band formation and is an important factor in material failure. How this texture evolves will be affected by grain size and grain boundary orientations. Electron backscattered diffraction EBSD is useful for characterizing texture, but it may also be used to characterize shear banding and damage progression. Results from experiments will illustrate how the microstructural changes in monotonically loaded tensile specimens can provide the damage evolution data necessary for predictive modeling of aluminum sheet metal components.




138.    House, J. W., J. Bingert, et al. (2002). Thermo-Mechanical Processing of Forged Tantalum Analyzed by OIM and X-Ray Diffraction. ICOTOM 13, Seoul, Korea, Trans Tech Publications Inc.

To control the mechanical response of pure tantalum requires tailoring the microstructure by carefully controlling thermo-mechanical processing. In this investigation the role of introducing an intermediate anneal prior to upset forging of a plate on microstructural evolution was investigated. Structural observations were made on surfaces of the plate located at the mid-plane and through-thickness. Plate material produced from the annealed billet material was more homogenous in grain structure and recrystallized with a higher ratio of {100}/{111} grain orientations. The limitations in mechanical properties that may be avoided by enhancing the textural and microstructural homogeneity through the introduction of an intermediate anneal are discussed.




139.    Howie, A. (1972). 5th Eur. Reg. Conf. for Electron Microscopy, Manchester.




140.    HS., C., G. A., et al. (2005). Effect of Orientation Noise on the Determination of Percolation Thresholds from Electron Back-Scatter Pattern Data. Textures of Materials - ICOTOM 14, Leuven, Belgium, Trans Tech Publications.

The effect of orientation noise in EBSP data on measurement of percolation threshold values has been investigated by use of computer simulated microstructures. A 2-D Monte Carlo Potts model run on a square lattice of size 200 x 200 was used to generate a microstructure containing approximately 150 grains. Orientations were then assigned to each of these grains to generate single texture component microstructures of differing texture tightness (“model” data). In order to simulate the effect of orientation noise on the experimental data, the orientation at each point in the 200 x 200 grid was adjusted in a manner consistent with experimental observations of the effect of orientation noise. The model data represent therefore an underlying real grain structure, and the noise-adjusted data represent the orientation map that would be measured using EBSP analysis at a given orientation noise level. The misorientation angle θ70% at which 70% of the grains were percolatively connected was then determined for both the ideal data and for the orientation noise adjusted data. A comparison of the two allows calibration of the extent to which percolation data may be incorrectly estimated by EBSP measurements.




141.    Hsiao, I. C. and J. C. Huang (2001). Characterization of grain boundary properties in superplastic Al based on alloys using EBSD. Materials Science Forum, Superplasticity in Advanced Materials, Orlando, FL.




142.    Hu, G. Y., I. Zuo, et al. (1996). The Cubic Texture Formation in Fe-3% Si Ribbons Produced by Direct Casting. Eleventh International Conference on Textures of Materials, Xi'an, China, International Academic Publishers.




143.    Hu, H. (1989). "On the Origin of Cube Texture in Face-Centered Cubic Metals." Scripta Metallurgica 23(6): 881-884.

Recently, a method has been devised for measuring boundary orientations using backscattered Kikuchi diffraction (BKD, otherwise known as electron backscattering, (EBS). To illustrate its application, piece of recrystallised 99.0% purity nickel sheet of rectangular cross section and thickness 0.125mm was annealed in vacuum for 1 hour at 1050 degree C so that the resulting grain size was approximately 100 mu m. Geometrical parameters for 47 grain boundaries were measured. The work reported demonstrates that BKD can be efficiently used to measure both the misori




144.    Hu, J. and D. Lin (2004). "Microstructural evolution of superplasticity in large-grained Ni-48Al intermetallics." Materials Science and Engineering A 371(1-2): 113-118.

Superplastic behavior has been found in large-grained Ni-48Al intermetallics with grain size of 200 µm. The large-grained Ni-48Al alloy exhibit deformation characteristics of most fine-grained superplastic alloys without the usual pre-requisites of a fine grain size and grain boundary sliding (GBS). Metallographic examination (OM) has shown that the average grain size of large-grained intermetallics decreases during superplastic deformation and a much finer grain size could be obtained after superplastic deformation. Transmission electron microscopy (TEM) and electron back-scattered diffraction (EBSD) observations have shown that there are great numbers of subgrain boundaries which form a network and among which the proportion of low and high angle boundaries increases with the increase of strain. The observed superplastic phenomenon is explained by continuously dynamic recovery and recrystallization (CDRR). During superplastic deformation. an unstable sub- grain network forms and these subboundaries absorb gliding dislocations and transform into low and high angle grain boundaries. A dislocation gliding and climbing process accommodated by subgrain boundary sliding, migration and rotation, enables the superplastic flow to proceed.




145.    Hu, J. and D.-L. Lin (2003). "Superplasticity in large-grained intermetallics." Transactions of Materials and Heat Treatment (China) 24(3): 31-36.

Superplastic behavior has been found in Fe3Al, Fe3Si, FeA1, Ni3Al, NiAl and TiAl alloys with large grain sizes (> 30-600 mu m). Metallographic examinations show that the average grain size of large-grained intermetallics decreases during superplastic deformation and a much finer grain size could be obtained after superplastic deformation. Electron back-scattered diffraction (EBSD) and transmission electron microscopy (TEM) observations show that there are great numbers of subgrain boundaries which form a network and among which the proportion of low and high angle boundaries increases with the increase of strain. The observed superplastic phenomenon is explained by continuously dynamic recovery and recrystallization (CDRR). During superplastic deformation, an unstable subgrain boundary network forms and these subboundaries are absorbing gliding dislocations and transform into iow and high angle grain boundaries. A dislocation gliding and climbing process accommodated by subgrain boundary sliding, migration and rotation, enables the superplastic flow to proceed.




146.    Hu, Y. M., W. Floer, et al. (1999). "Microstructurally short fatigue-crack initiation and growth in Ti-6.8Mo-4.5Fe-1.5Al." Materials Science and Engineering A 278(1-2): 170-180.

Microstructurally short fatigue crack initiation and growth was studied in single-phase titanium alloy Ti-6.8Mo-4.5Fe-1.5Al (TIMETAL(R) LCB) by means of the electron back-scatter diffraction (EBSD) technique. The evolution of surface cracks was traced by interrupting fatigue testing to obtain the details of the crack initiation and growth process. Cracks were found to initiate preferentially either at slip bands or grain boundaries (GBs) during cyclic loading, both of these two types of cracking being usually associated with GB constraints. EBSD examination showed that high-misorientation-angle conditions are favorable for crack nucleation. An elastic-plastic incompatibility mechanism is proposed to account for the crack initiation behavior. Furthermore, short crack growth behavior was found to be closely related to the misorientation between the grains involved, the GB direction and the loading direction with respect to the crack plane. The most favorable conditions for the transmission of a short crack from one grain to another were: (i) the operative slip plane in the next grain lies at a low angle with respect to the crack plane; (ii) the angle between the surface trace of the operative slip plane (or GB) in the expected cracking grain and the loading axis is close to 90 degrees. In addition, the crack growth behavior was found to be influenced by the interaction between short cracks. (37 References).




147.    Hu, Y., V. Randle, et al. (2004). Role of Silicon Content and Final Annealing Temperature on Microtexture and Microstructure Development in Non-Oriented Silicon Iron. Second Joint International Conference on Recrystallization and Grain Growth, ReX & GG2, SF2M, Annecy, France, Trans Tech Publications Ltd.




148.    Huang, J. C., I. C. Hsiao, et al. (2000). "EBSD study on grain boundary characteristics in fine-grained Al alloys." Scripta Materialia 43(No. 3): 213-20.




149.    Huang, L., L. Pu, et al. (2005). "Controlled growth of well-faceted zigzag tin oxide mesostructures." Applied Physics Letters 87.

Reproducibly high-yield growth of zigzag fibers and well-faceted nanobelts of SnO2 was achieved via tuning the reactant vapor. The investigation of the morphological evolution via scanning electron microscopy and transmission electron microscopy hints that the formation of the zigzag SnO2 fiber is based on the pregrowing SnO2 nanobelt. The elucidation of the growth mechanism should provide a fully controlled route for reproducibly high-yield growth of zigzag fibers of SnO2 and give some valuable hints to synthesis other zigzag mesostructures. Optical characterizations of these structures show very weak defect-related emissions.




150.    Huang, L., L. Pu, et al. (2005). "Light propagation tuned by periodic junctionprisms within well-faceted ZnO fibers." Optics Express 13(14).

Well-faceted ZnO fibers with periodic junction-prisms were synthesized using conventional chemical vapor deposition. The characterization of the fibers by optical and fluorescence microscopy showed that the outer facets of the crystalline fibers provide excellent mirror-like surfaces for guiding light propagation along the fiber stem as well as the periodic junction-prisms. The structure-related optical properties can be fully explained by a microstructural model. The proposed model explains as the decrease in luminance at the junction-prisms is caused by refraction and total or partial reflection of light. The model also explains the luminance enhancement at the junction- prisms is related to waveguiding of the green emission of the ZnO fibers. Further integration of the ZnO junction-prisms into microdevices should provide the microscale modulation for light with different wavelengths, and could be potentially used for enhanced light-illumination arrays.




151.    Huang, L., S. Wright, et al. (2004). "ZnO well-faceted fibers with periodic junctions." Journal of Physical Chemistry B 108(52): 19,901-19,903.

ZnO well-faceted microfibers with periodic junctions were prepared by an evaporation and deposition process. The junctions with spacings of 5-30 µm presented concavo-concave morphologies, and the spacings could be changed with the growth conditions. The anisotropic growth mechanism was investigated by X-ray diffraction (XRD), energy-dispersive X-ray (EDX) analysis, scanning electron microscopy (SEM), and electron backscatter diffraction (EBSD). The photoluminescence (PL) and PL microscopy studies showed the structure-related optical character and that the well-faceted and modulated fibers could serve as microscale waveguides and emit enhanced green lights at the junctions under UV excitation. These functional structures should make possible the creation of microscale light-emitting arrays as well as bar codes used in biotechnology and electronics.




152.    Huang, L., S. Yang, et al. "Micro-Barcodes Emitting Green Light: ZnO Well-Faceted Fibers with Periodic Junctions."




153.    Huang, M. (2004). "The n-point orientation correlation function and its application." International Journal of Solids and Structures 42(5-6): 1425-1441.

The properties of a polycrystal can be treated from a statistical point of view. Herein the concept of the n-point orientation correlation function (the n-OCF) is presented in detail. The relations among the 2-point microtexture coefficients, statistical symmetry, and crystallographic symmetry are given for an orthorhombic aggregate of cubic crystallites. As an application of the n-OCF, we obtain a formula for the effective elastic stiffness tensor pertaining to an orthorhombic aggregate of cubic crystallites




154.    Huang, X. and D. J. Jensen (2000). EBSD Contra TEM Characterization of a Deformed Aluminum Single Crystal. Electron Backscatter Diffraction in Materials Science. A. J. Schwartz, M. Kumar and B. L. Adams. New York, Kluwer Academic/Plenum Publishers: 265-275.




155.    Huang, X., M. C. Chaturvedi, et al. (1997). "The Effect of Grain Boundary Segregation of Boron in Cast Alloy 718 on Haz Microfissuring - A Sims Analyis." Acta Materialia 45(8): 3095-3107.




156.    Huang, X., W. Yang, et al. (2004). "Enhanced ductility in coarse grained Fe3Al alloys." Intermetallics 12(7-9): 1019-1023.

Microstructural and textural evolution during high temperature deformation of a Fe3Al based alloy have been characterized using transmission electron microscopy and electron backscatter diffraction. A large number of dislocation boundaries with very low misorientation angles and high dislocation density were observed in the matrix of deformed grains in the strain range 0.2–1.26 (fracture strain). A <110> fibre texture was observed in the sample deformed to failure, which can be accounted for by the activation of <111> slip in the B2 structured Fe3Al. The microstructural and textural evolution, combined with the measured strain rate sensitivity and activation energy for deformation suggests that the deformation is controlled by a glide controlled dislocation mechanism.




157.    Huang, Y. and F. J. Humphreys (1999). "Measurements of grain boundary mobility during recrystallization of a single-phase aluminum alloy." Acta Materialia 47(7): 2259-68.

A combination of in situ annealing and electron backscattered diffraction in the SEM has been used to determine the mobility of high angle grain boundaries in a deformed single-phase Al–Si alloy. It is found that the boundary velocity is directly proportional to the driving pressure and that the activation energy for boundary migration over all the conditions investigated is consistent with control by lattice diffusion of the solute. It is confirmed that tilt boundaries of recrystallized grains misoriented by 40±10° about axes within ±10° of <111> have an increased mobility compared to other high angle boundaries, whereas the mobilities of 40°<111> twist boundaries are similar to those of general high angle boundaries. The mobility maximum for the 40°<111> tilt boundaries is very broad, which is in contrast to the sharp mobility peaks reported for curvature-driven grain growth, and possible reasons for these differences are discussed.




158.    Huang, Y. and F. J. Humphreys (2001). "Measurements of subgrain growth in a single-phase aluminum alloy by high-resolution EBSD." Materials Characterization 47(3-4): 235-240.

Single crystals of {100}<100> and {110}<100> orientations of a high-purity Al–0.05% Si single-phase aluminum alloy have been deformed under plane strain compression at elevated temperatures. The deformed crystals of the {100}<100> orientation contained bands of subgrains of a range of size and misorientation, whereas the {110}<100> crystals gave very uniform microstructures. The specimens were annealed at temperatures between 300 and 450°C and measurements of the subgrain growth have been made using high-resolution electron backscattered diffraction (EBSD) in a field emission gun scanning electron microscope (FEGSEM). Detailed analysis of deformed and annealed crystals revealed a strong correlation between subgrain growth and misorientation, and the analysis of the data enabled the mobility of low-angle boundaries and activation energies in the misorientation range of 2–20° to be determined.




159.    Huang, Y. and F. J. Humphreys (2003). The Pining of Grain Boundaries During the Recrystallization of an Al-0.3Mn-0.15Si Alloy. Thermec' 2003, Leganés, Madrid, Spain, Trans Tech Publications Ltd.

The technique of combined SEM in-situ annealing and EBSD was used to investigate the effect of second-phase particles on grain boundary migration during the recrystallization of cold deformed Al-0.3Mn-0.15Si single crystals of Goss orientation {110} <001>. It was found that particles substantially retarded the start of the growth of the artificially initiated nuclei although the boundary mobilities obtained were quite close to those of the single-phase Al-3.0Mn alloy. The recystallized grains of about 40°/<111> relationship with the deformed matrix grew the fastest, particularly at high annealing temperatures, although at lower temperatures random boundaries were often found to migrate at similar rates. The experimental results are explained in terms of the effect of Zener pinnning of migrating boundaries by second-phase particles.




160.    Huang, Y. D., W. Y. Yang, et al. (2003). "Formation of ultrafine grained ferrite in low carbon steel by heavy deformation in ferrite or dual phase region." Journal of Materials Processing Technology 134: 19-25.




161.    Huang, Y., F. J. Humphreys, et al. (2000). "The Annealing Behavior of Deformed Cube-Oriented Aluminum Single Crystals." Acta Materialia 48: 2543-2556.

Single crystals of the {001}<100> cube orientation of a dilute single-phase Al-Si alloy have been deformed in plane strain compression at temperatures between 300 and 500°C at strain rates between 0.5 and 50/s. The stability of the cube orientation was found to be dependent on the deformation conditions, which is in agreement with previous work. The deformed crystals contained bands of subgrains of a range of sizes and misorientations. Detailed EBSD analysis of deformed and annealed crystals revealed a strong correlation between subgrain growth and misorientation, and analysis of the data enabled the mobility of low angle grain boundaries in the misorientation range 5-20° to be determined in the temperature range 300-450°C. It was found that the boundary mobility increased with increasing misorientation up to ~15-20° and thereafter reached a plateau. The activation energies of migration were consistent with control by lattice diffusion of Si in Al and the activation energy was found to increase with increasing misorientation.




162.    Huang, Y., F. J. Humphreys, et al. (2002). "The application of a hot deformation SEM stage, backscattered electron imaging and EBSD to the study of thermomechanical processing." Journal of Microscopy 208(1): 18.

The technique of combining in situ hot-deformation and high resolution electron backscattered diffraction (EBSD) has been applied to study the mechanisms operating during the thermomechanical processing of metals. A simple hot tensilestraining stage is installed in a field emission gun scanning electron microscope equipped with an EBSD system and has been used successfully for a number of preliminary investigations. These investigations include substructure formation, dynamic subgrain and grain growth, superplastic deformation in aluminium alloys, and dynamic recrystallization in copper. Despite the surface topography, which inevitably increases during plastic deformation, channelling contrast backscattered electron micrographs have been successfully obtained after strains of up to ~50%. Good quality EBSD maps have been obtained after strains of up to 100%. Most observations and measurements from the in situ experiments are consistent with what is known about the mechanisms occurring in the bulk. The microstructures revealed in the centre of the in situ samples after later repolishing are generally similar to those at the surface.




163.    Huang, Y., F. J. Humphreys, et al. (2003). In situ observations of microstructural evolution during deformation of supral 100. Superplasticity in Advanced Materials: 8th International Conference on Superplasticity in Advanced Materials, ICSAM 2003, Oxford, UK, Trans Tech Publications.

A commercially processed SUPRAL 100(AA2004) sheet material of nominal composition: Al-6wt%Cu-0.4wt%Zr, has been deformed in-situ in a field emission gun scanning electron microscope at a temperature of 450 or discon C at strain rates of (1 similar to 2.5)x10/sup-4/s/sup-1/ to a total elongation of similar to 100%. The microstructural evolution in the surface of the specimen was monitored during deformation. Straining was stopped at intervals to allow high resolution EBSD measurements to be made and the evolution of texture, grain size and the fraction of high angle grain boundaries was obtained. It was found that the fraction of high angle grain boundaries increased with strain and consequently a fine grain superplastic (SP) microstructure developed at a true strain of about 0.5. A previous model for geometrical dynamic recrystallization was found to satisfactorily describe the characteristics of the microstructural evolution.




164.    Hughes, D. A. and A. Kumar (1996). Grain Subdivision and the Development of Local Orientations in Rolled Tantalum. Tantalum, Anaheim, California, TMS.




165.    Hughes, D. A. and N. Hansen (1997). "High-Angle Boundaries Formed by Grain Subdivision Mechanisms." Acta Materialia 45(9): 3871-3886.

Deformation of metals from medium to high strains introduces significant changes in the microstructure and the texture. The microstructure evolves into a lamellar structure with boundaries of small to medium misorientation angles mixed with high angle boundaries. The latter category consists of deformation induced boundaries plus the original grain boundaries. The number of deformation induced high angle boundaries is significantly larger than the number of original grain boundaries. Mechanisms for the formation of the deformation induced boundaries are suggested based on grain subdivision processes which can lead to formation of different texture components within an original grain. The distribution of their misorientations is estimated based on these mechanisms. This estimate is compared to experimental findings for Al, Ni and Ta deformed to large strain by rolling or in torsion. This estimate and the findings are discussed and good support is established for the basic assumption that grain subdivision accompanied by a strong texture evolution can lead to a very significant increase in the fraction of high angle boundaries in a deformed metal. These findings provide the essential physical background for the construction of theoretical models for the distributions.




166.    Huh, M. Y., H. D. Kim, et al. (2002). Formation of Shear Texture and Ultra-fine Grains in Warm Rolled AA 3004 Sheets. ICOTOM 13, Seoul, Korea, Trans Tech Publications Inc.

The evolution of texture and microstructure during warm rolling and subsequent annealing in aluminum 3004 alloy sheets was investigated by X-ray texture measurements and microstructure observations. Warm rolling at 250°C led to the development of strong through thickness texture gradients with shear textures at the surface layer and regular rolling textures in the center of the sheets. FEM simulations indicated that these texture gradients are caused by pronounced strain gradients throughout the sheet thickness. Upon recrystallization annealing, in the sheet center the characteristic cube-recrystallization texture devleoped, while in the surface layers with a pronounced shear texture, continuous recrystallization took place which led to the formation of a very fine grained microstructure. It is concluded that the very complex strain history in the near-surface layers together with the resulting high work-hardening rate gave rise to the formation of the ultra-fine grains with an average size smaller than 2 µm.



167.    Huh, M. Y., J. C. Lee, et al. (2004). "Formation of a random texture and ultrafine grains in AA 3003 aluminium alloy during the repeated shear deformation introduced by continuous confined strip shearing." Materials Science and Technology 20(7): 819-824.

To investigate the microstructural development and corresponding texture evolution during repeated shear deformation, specimens of AA 3003 Aluminium alloy were deformed by continuous confined strip shearing based on equal channel angular pressing. Strip specimens were deformed by the shear forming process during up to eight passes, equivalent to effective strains of.4.8. Texture evolution in the AA 3003 strips during the shear deforming process was studied by comparing the experimentally measured textures with simulated ones. Electron backscattered diffraction was employed to investigate detailed changes in microtextures and microstructures during repeated shear deformation. Softening associated with deformation is believed to be responsible for the formation of ultrafine grains and the random texture resulting from repeated shear deformation.




168.    Huh, M. Y., J. C. Lee, et al. (2004). Evolution of annealing textures and microstructures in AA 3103 after cold rolling and repeated shear deformation. Fifth Pacific Rim International Conference on Advanced Materials and Processing PRICM-5, Beijing, China, Trans Tech Publications.

The evolution of annealing textures and microstructures in the aluminum alloy 3103, which was subjected to deformation by either cold rolling or equal channel angular rolling (ECAR), was investigated. Samples of AA 3103 sheets were repeatedly deformed by ECAR up to six passes. In addition, AA 3103 was cold rolled to the same hardness level of the ECARed samples. Upon annealing, the cold rolled sample was recrystallized by the discontinuous recrystallization which gave rise to the formation of the cube texture and large grains bigger than 30 µm. In contrast, the ECARed sample was recrystallized by extended recovery which led to the formation of ultra-fine grains having a size smaller than 3.5 µm. Copyright 2005 Trans Tech Publications, Switzerland.




169.    Huh, M. Y., J. P. Lee, et al. (2004). "Formation of shear texture and ultra-fine grains during equal angular channel rolling and subsequent annealing in AA 3003 sheet." Materials Science Forum 449-452: 873-876.

The evolution of texture and microstructure during the equal channel angular rolling (ECAR) and subsequent annealing in aluminum alloy 3003 sheets was investigated. The tools of ECAR were designed to provide a constant shear deformation of the order of 0.5 per passage while preserving the original sheet shape. Samples of the aluminum alloy 3003 sheets were repeatedly deformed by ECAR up to twelve passages. Shear textures developed after the first passage of ECAR. However, the intensity of shear texture components decreased with increasing number of ECAR passages. After a large number of ECAR passages, a random texture developed at the expense of shear texture components. Observations by TEM and EBSD revealed that the degree of misorientations within the deformed grains increased with increasing number of ECAR passages. After recrystallization annealing, samples deformed by ECAR displayed pronounced {111}//ND fiber orientations. The annealed sheets comprising of ultra-fine grains were successfully produced in the samples deformed by a large number of ECAR passages.




170.    Huh, M. Y., Y. S. Cho, et al. (1998). "Effect of lubrication on the evolution of microstructure and texture during rolling and recrystallization of copper." Materials Science and Engineering A 247: 152-164.

Two polycrystalline copper specimens were deformed by cold rolling with and without lubrication so as to achieve different deformed microstructures. The effect of the different rolling procedures on the evolution of microstructure and texture during rolling and recrystallization was studied by microstructural observations and X-ray texture analysis. In addition, local orientations in the as-deformed state were determined by selected area diffraction (SAD) in a transmission electron microscope (TEM) and, after recrystallization, by electron backscattering diffraction (EBSD) in a scanning electron microscope (SEM). Whereas the rolling textures of the two differently rolled sheets were surprisingly similar, the microstructures strongly differed in so far as the sample rolled without lubrication contained a much larger amount of shear bands. The present results suggest that the shear component ε13caused by friction during dry rolling can effectively be dissipated by shear band formation, resulting in a rather homogeneous overall rolling texture. With regard to nucleation of recrystallization, shear bands are known to cut the typical nucleation sites of the cube-orientation, the main recrystallization texture component of rolled copper, but they are also able to act as new nucleation sites. Furthermore, growth of the new recrystallized grains is hindered by the shear bands because of microstructural and orientation discontinuities at the matrix–shear band interfaces. This led to a strong retardation of the recrystallization process and gave rise to a very fine grained microstructure and a weak recrystallization texture in the specimen cold rolled without lubrication.




171.    Humbert, M., B. Gardiola, et al. (2002). "Modelling of the variant selection mechanism in the phase transformation of HSLA steel produced by compact strip production." Acta Materialia 50: 1741-1747.

The ferrite and residual austenite textures of a microalloyed steel (HSLA) produced by Compact Strip Production (CSP) were determined by X-ray diffraction. At the same time, the individual orientations of neighbouring inherited ferrite grains and austenite grains were measured by EBSD. Orientation relations between the parent austenite and the inherited ferrite have been assessed. Knowing these orientation relations and the parent austenite texture, the simulation of the texture of the inherited ferrite texture has been performed without variant selection. The comparison of this calculated texture with the experimental ferrite texture shows differences due to a variant selection mechanism occurring during the phase transformation at cooling. A modelling of a variant selection mechanism based on the elastic anisotropy of the parent austenite leads to a simulated inherited texture with the main characteristics of the experimental ferrite texture.




172.    Humbert, M., F. Wagner, et al. (1995). "Determination of the Orientation of a Parent Beta-Grain from the Orientations of the Inherited Alpha-Plates in the Phase-Transformation from Body-Centered-Cubic to Hexagonal Close-Packed." Journal of Applied Crystallography 28(OCT): 571-576.




173.    Humbert, M., H. Moustahfid, et al. (1994). "Evaluation of the high-temperature texture of the beta-phase of a Ta6V sample from the individual orientations of grains of the low-temperature alpha- phase." Scripta Metallurgica et Materialia 30(3): 377-382.

Describes an indirect method of determination of the beta texture of Ti-Al-V alloys, based on the fact that a grain of the high temperature beta phase transforms into different alpha plates during the phase transformation, where the alpha plate orientation is correlated with the orientation of the former beta grain. The determination of the orientation of the parent beta grain is possible, provided that the boundaries of the parent beta grain are clear, the number of different plate orientations sufficient, and that a strict orientation relation between the alpha and beta lattices exists. Using this method, the authors have obtained the texture of the beta phase of an alloy of TA6V from the determination of the orientations of a population of parent beta grains, the orientation of a given beta grain, deduced by correlating the orientations of the corresponding alpha plates measured by electron back scattering patterns (EBSP). (6 References).




174.    Humbert, M., N. Gey, et al. (1996). "Determination of a mean orientation from a cloud of orientations. Application to electron back-scattering pattern measurements." Journal of Applied Crystallography 29(6): 662-666.

Two approaches to the measurement of elastic strains from electron channelling patterns (ECPs) and electron backscatter diffraction (EBSD) patterns are assessed. Analysis of the shift in channelling (or Kikuchi) line positions has been shown to yield strain sensitivities of up to 3 parts in 104 when {10 10 0} lines in ECPs are used. The lack of such fine detail in EBSD patterns restricts such methods to strains at least one order of magnitude greater. For EBSD an alternative method is presented in which elastic strains are determined from measurements of small shifts in zone axis positions. The strain sensitivity of the method was found to be 2 parts in 104. Measurements, using this method, of elastic strains in Si1-xGex epitaxial layers gown on Si substrates gave excellent agreement with X-ray diffraction data. The EBSD technique is capable of determining elastic strain variations at submicrometre resolution. (16 References).




175.    Humbert, M., N. Gey, et al. (2005). Study and Modelling Of Some Variant Selections In BCC to HCP Phase Transformations. Textures of Materials - ICOTOM 14, Leuven, Belgium, Trans Tech Publications.

One very often observes that the texture inheritance in BCC to HCP phase transformation shows variant selections, even though no external stress field is applied. These variant selections are related to the metallurgical state, the microstructure and the texture of the parent phase. From our own investigations, we came to the conclusion that the variant selections we observed in some phase transformations of various materials were influenced at different degrees by the elastic behaviour of the parent phase. Considering the transformation strain of each variant and the elastic anisotropy of the parent, we have build variant selection models based on energy minimum of elastic strain and assuming different types of interactions. The simulation results of texture transformation of a zircalloy sample show that the elastic characteristics of the parent phases are key parameters involved in the variant selection.




176.    Humbert, M., S. R. Dey, et al. (2005). Calculation of the parent hcp grain orientation from inherited variants in the hcp to t and in the hcp to cc phase transformations Application to the α - γ transformation in TiAl-based alloys. Textures of Materials - ICOTOM 14, Leuven, Belgium, Trans Tech Publications.

The orientations of the inherited tetragonal (resp. cubic) variants are calculated from the parent hcp orientation in the case of a strict orientation relation. The numbering of the variants is proposed, as well as the misorientations between them. Conversely, a method for calculating the parent hcp orientation from a sufficient number of inherited variants is proposed. It is based on orientation correlating and orientation averaging, and it is particularly useful when the inherited variants are not exactly related to the parent orientation by a strict orientation relation or when the orientations of the inherited volumes slightly vary at different locations of the variant. The method is illustrated by considering the α to γ phase transformation taking place in TiAl-based alloys




177.    Humphreys, F. J. (1988). Experimental Techniques for Microtexture Determination. ICOTOM 8, Santa Fe, New Mexico, The Metallurgical Society.




178.    Humphreys, F. J. (1999). Determination of microtexture by EBSD at high spatial resolution in a FEGSEM. Twelfth International Conference on Textures of Materials (ICOTOM 12), McGill University, Montreal, Canada, NRC Research Press.




179.    Humphreys, F. J. (1999). "Microstructural Characterization by High-Resolution Electron Backscattered Diffraction in the Fegsem - Competition for the TEM." Institute of Physics Conference Series(161): 429-434.




180.    Humphreys, F. J. (1999). "Quantitative Metallography by Electron Backscattered Diffraction." Journal of Microscopy 195(3): 170-185.

Although electron backscattered diffraction (EBSD) in the scanning electron microscope is used mainly to investigate the relationship between local textures and micro-structures, the technique has now developed to the stage where it requires serious consideration as a tool for routine quantitative characterization of microstructures. This paper examines the application of EBSD to the characterization of phase distributions, grain and subgrain structures and also textures. Comparisons are made with the standard methods of quantitative metallography and it is shown that in many cases EBSD can produce more accurate and detailed measurements than the standard methods and that the data may sometimes be obtained more rapidly. The factors which currently limit the use of EBSD for quantitative microstructural characterization, including the speed of data acquisition and the angular and spatial resolutions, are discussed, and future developments are considered. Results cited are mainly from work on Al alloys, including 5182.




181.    Humphreys, F. J. (2001). "Review - Grain and Subgrain Characterization by Electron Backscatter Diffraction." Journal of Materials Science 36(16): 3833-3854.

The application of automated Electron Backscatter Diffraction (EBSD) in the scanning electron microscope, to the quantitative analysis of grain and subgrain structures is discussed and compared with conventional methods of quantitative metallography. It is shown that the technique has reached a state of maturity such that linescans and maps can routinely be obtained and analysed using commercially available equipment and that EBSD in a Field Emission SEM (FEGSEM) allows quantitative analysis of grain-subgrains as small as ~0.2 μm. EBSD can often give more accurate measurements of grain and subgrain size than conventional imaging methods, often in comparable times. Subgrain/cell measurements may be made more easily than in the TEM although the limited angular resolution of EBSD may be problematic in some cases. Additional information available from EBSD and not from conventional microscopy, gives a new dimension to quantitative metallography. Texture and its correlation with grain or subgrain size, shape and position are readily measured. Boundary misorientations, which are readily obtainable from EBSD, enable the distribution of boundary types to be determined and CSL boundaries can be identified and measured. The spatial distribution of Stored Energy in a sample and the amount of Recrystallization may also be measured by EBSD methods.




182.    Humphreys, F. J. (2004). "Characterisation of fine-scale microstructures by electron backscatter diffraction (EBSD)." Scripta Materialia 51(8 (Special Issue)): 771-776.

Recent developments in instrumentation and software now enable grain structures >0.1 µm to be quantitatively characterised by EBSD in conjunction with a field emission gun scanning electron microscope. The paper discusses the advantages and limitations of the technique. Copyright 2004 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.




183.    Humphreys, F. J. (2004). Nucleation in Recrystallization. Second Joint International Conference on Recrystallization and Grain Growth, ReX & GG2, SF2M, Annecy, France, Trans Tech Publications Ltd.




184.    Humphreys, F. J. (2004). "Reconstruction of grains and subgrains from electron backscatter diffraction maps." Journal of Microscopy 213(Pt. 3): 247-256.

Electron backscatter diffraction maps are capable of yielding a substantial amount of quantitative information about grains, subgrains and boundaries, and the amount and quality of the data may be substantially increased if the pixels of the map are re-analysed so as to ‘reconstruct’ complete grains or subgrains. The paper discusses the various methods of grain reconstruction and the use of such methods to obtain microstructural information correlating the parameters of dimension, position, orientation and misorientation, which cannot usually be obtained by other means. Grain reconstruction also reveals the nature, location and contacts of all the triple junctions in the microstructure, and the paper discusses two important examples of how these data may be further analysed using automated routines. Boundary connectivity and the length and direction of likely paths along which grain boundary events such as creep fracture or stress corrosion may occur can readily be determined. The overall alignment of boundaries in deformed metals, with respect to the crystallography and the deformation geometry, may be determined as a function of the length and misorientation of the boundary segments.




185.    Humphreys, F. J. and I. Brough (1999). "High-resolution electron backscatter diffraction with a field-emission gun scanning electron-microscope." Journal of Microscopy 195(Pt. 1): 6-9.

A scanning electron microscope with a thermal field emission gun (FEGSEM) is found to offer significant improvements in electron backscatter diffraction performance over a conventional W-filament scanning microscope. The spatial resolution is improved by a factor of approximate to 3 in the FEGSEM and is optimized at probe currents of 50-300 nA and at 10-15 keV. The angular accuracy is optimized at probe currents above approximate to 150 nA and at 30 keV.




186.    Humphreys, F. J. and M. Ferry (1996). "Combined in-situ annealing and EBSD of deformed aluminium alloys." Materials Science Forum 217-222(pt 1): 529-534.

The application of an SEM heating stage and EBSD system to the study of recrystallization and grain growth in aluminium alloys is discussed. It is shown that the development of the recrystallized microstructure and the growth of grains during recrystallization are similar to those occurring in the interior of a specimen. However, the presence of a free surface influences several aspects of annealing, including recovery and grain growth. It is found that annealing twins are formed more frequently at a free surface than in the specimen interior, and the significance of this is discussed. (Author abstract) [References: 12]




187.    Humphreys, F. J. and M. Ferry (1997). "Applications of Electron Backscattered Diffraction to Studies of Annealing of Deformed Metals." Materials Science and Technology 13(1): 85-90.




188.    Humphreys, F. J. and M. G. Ardakani (1994). "The Deformation of Particle-Containing Aluminum Single-Crystals." Acta Metallurgica et Materialia 42(3): 749-761.




189.    Humphreys, F. J. and M. G. Ardakani (1996). The Effect of Orientation on Zener Pinning in Cu-Al2O3 Crystals. Eleventh International Conference on Textures of Materials, Xi'an, China, International Academic Publishers.




190.    Humphreys, F. J. and P. S. Bate (2005). The Alignment of Low Angle Boundaries During Deformation. Textures of Materials - ICOTOM 14, Leuven, Belgium, Trans Tech Publications.

Two methods of automatically determining boundary alignments from EBSD maps are discussed and shown to produce comparable results. Measurements of Al-0.1Mg and IF steel, deformed at room temperature, confirm that the alignment of low angle boundaries is primarily a function of the deformation mode, rather than the crystallography. During the high temperature deformation of aluminium, the lagbs maintain a large angle of inclination to the rolling direction (>35°) even at large strains, which is consistent with the boundaries being of transient character during deformation.




191.    Humphreys, F. J. and P. S. Bate (2006). "Measuring the alignment of low-angle boundaries formed during deformation." Acta Materialia 54(3): 817-829.

The determination of the alignments of low-angle boundaries by transmission electron microscopy and electron backscattering diffraction (EBSD) methods is discussed. Two methods of automatically determining boundary alignments from EBSD maps, the marching Radon transform and triple junction analysis methods, are compared and shown to produce comparable results. Measurements of Al–0.1 Mg deformed both at room temperature and elevated temperatures confirm that the alignment of low-angle boundaries is primarily a function of the deformation mode, rather than the crystallography.




192.    Humphreys, F. J., P. S. Bate, et al. (2001). "Orientation averaging of electron backscattered diffraction data." Journal of Microscopy 201, Pt. 1: 50-58.

The use of data averaging to improve the angular precision of electron backscattered diffraction (EBSD) maps is discussed. It is shown that orientations may be conveniently and rapidly averaged using the four Euler-symmetric parameters which are coefficients of a quaternion representation. The processing of EBSD data requires the use of an edge preserving filter, and a modified Kuwahara filter has been successfully implemented and tested. Three passes of such a filter have been shown to reduce orientation noise by a factor of ~10. Application of the method to deformed and recovered aluminum alloys has shown that such data processing enables small subgrain misorientation (<0.5°) to be detected reliably.




193.    Humphreys, F. J., Y. Huang, et al. (1999). "Electron backscatter diffraction of grain and subgrain structures - resolution considerations." Journal of Microscopy - Oxford 195(Pt. 3): 212-216.

Characterization of microstructures containing small grains or low-angle grain boundaries by electron backscattered diffraction (EBSD) is limited by the spatial and angular resolution limits of the technique. It was found that the best effective spatial resolution (60 nm) for aluminium alloys in a tungsten-filament scanning electron microscope (SEM) was obtained for an intermediate probe current which provided a compromise between pattern quality and specimen interaction volume. The same specimens and EBSD equipment when used with a field-emission gun SEM showed an improvement in spatial resolution by a factor of 2-3. For characterizing low-angle boundary microstructures, the precision of determining relative orientations is a limiting factor. it was found that the orientation noise was directly related to the probe current and this was interpreted in terms of the effect of probe current on the quality of the diffraction patterns.




194.    Hunter, A. and M. Ferry (2002). "Comparative study of texture development in strip-cast ferritic and austenitic stainless steels." Scripta Materialia 47(5): 349-355.




195.    Hunter, A. and M. Ferry (2002). "Evolution of Microstructure and Texture During Casting of AISI 304 Stainless Steel Strip." Metallurgical and Materials Transactions A 33A(No. 12): 3747-3754.

The solidification behavior of AISI 304 stainless steel strip was studied using a melt-substrate contact apparatus, whereby a copper substrate embedded in a moving paddle is rapidly immersed into a steel melt to produce thin (~1 -mm gage) as-cast coupons. For cases where other casting conditions were kept constant, the effect of substrate topography and melt superheat on the development of microstructure and texture during solidifiation was studied using electron backscatter diffraction (EBSD) and optical microscopy. It was found that nucleation and growth of grains during solidification were influenced both by substrate topography and melt superheat. A ridged substrate produced a high density of randomly oriented grains at the chill surface with the preferred groowth of <001>-oriented grains perpendicular to the substrate wall producing a coarse columnar grain structure exhibiting a strong <001> fiber texture at the strip center. In contrast, a smooth substrate resulted in a lower nucleation density to produce a very coarse-grained columnar microstructure with moderate and essentially constant <001> fiber texture throughout the strip thickness. By the manipulation of casting parameters it is possible to produce strip-cast austenitic stainless steel with a particular microstructure and texture.




196.    Hunter, A. and M. Ferry (2002). "Texture Enhancement by Inoculation during Casting of Ferritic Stainless Steel Strip." Metallurgical and Materials Transactions A 33A(5): 1499-1507.

Melt-substrate contacting experiments, designed to approximate conditions encountered during strip casting, were carried out to produce as-cast ferritic stainless steel strip. The results show that the inoculation of the melt to produce TiN particles, together with casting onto a smooth substrate, results in the optimum conditions for nucleation and subsequent growth of an exceedingly high volume fraction of ferrite grains with < 001 > oriented within a few degrees of the normal direction (ND) of the strip surface. It is argued that, during casting, TiN particles either nucleate or deposit onto the substrate with < 001 > parallel to the ND, and since these particles exhibit crystallographic features similar to δ-ferrite, subsequent epitaxial growth inherits the initial particle orientation. Such oriented nucleation of ferrite from a smooth substrate results in the optimum heat-transfer conditions for further growth of dendrites with < 001 > perpindicular to the substrate, thus producing the intense through-thickness < 001 >//ND fiber texture in the as-cast strip. The potential for producing grain-oriented silicon iron by direct strip casting is outlined.




197.    Hupalo, M. F., A. F. Padilha, et al. (2004). Texture and microstructure evolution during cold swaging and recrystallization of oligocrystalline INCOLOY(R) MA 956. 2nd International Conference on Texture and Anisotropy of Polycrystals (ITAP 2), Metz, France, Balaban Publishers; Scitec Publications, Switzerland.

Cold swaged and annealed samples of INCOLOY(R) MA 956 (UNS S67956) were investigated using light optical microscopy (LOM), transmission electron microscopy (TEM), X-ray diffraction (XRD), electron backscattered diffraction (EBSD), and Vickers microhardness testing. The as-received oligocrystalline material presented a strong <111>-texture parallel to the longitudinal direction of the bar. This texture results from secondary recrystallization promoted by zone annealing. The microstructure in the deformed state was found to be very inhomogeneous. Deformation bands were observed in all grains. The extent of deformation banding varied from grain to grain in terms of morphology and spacing. The deformation substructures were found to be very different in each grain. A sharp <110>-fiber texture was developed during plastic deformation becoming more pronounced with increasing strain. Intense recovery during annealing has been observed in this alloy. Recrystallization did not change the texture significantly.




198.    Hupalo, M. F., A. M. Kliauga, et al. (2004). "Cold swaging, recovery and recrystallization of oligocrystalline INCOLOY MA 956-part I: Deformed state." ISIJ International 44(11): 1894-1901.

Oxide dispersion strengthened (ODS) superalloys combine high temperature strength and excellent corrosion and oxidation resistances. INCOLOY MA 956 is an iron-based ODS superalloy containing about 1 % (volume) of fine and uniformly dispersed Y2O3 particles in a ferritic matrix. In the present work a coarse-grained (oligocrystalline) bar of MA 956 alloy was cold deformed by rotary swaging to reductions in area of 20, 47, 61, and 72%. Microstructural characterization of deformed samples was performed using light optical microscopy (LOM), X-ray diffraction (XRD), electron backscatter diffraction (EBSD), and Vickers micro-hardness testing. The microstructure in the deformed state was found to be very inhomogeneous. Deformation bands were observed in all grains. The extent of deformation banding varies from grain to grain in terms of morphology and spacing. The deformation substructures were found to be very different in each grain. A sharp <110>-fiber texture was developed during plastic deformation becoming more pronounced with increasing strain.




199.    Hupalo, M. F., A. M. Kliauga, et al. (2004). "Cold swaging, recovery and recrystallization of oligocrystalline INCOLOY MA 956-part II: Annealed state." ISIJ International 44(11): 1902-1910.

The combination of a coarse-grained structure (oligocrystalline material), a strong initial texture, and the presence of fine particles make ODS superalloys like INCOLOY MA 956 very interesting materials for recrystallization studies. In the present paper, we have investigated the annealing behavior of the MA 956 alloy deformed by cold swaging to reductions of 20, 47, 61, and 72% followed by annealing at temperatures ranging from 600 to 1 45000 and 85 C. Light optical, scanning, and transmission electron microscopy were used to follow the microstructural changes upon annealing. Orientations of individual grains as well as microtexture were determined by electron backscatter diffraction (EBSD). Recrystallization texture was determined by X-ray diffraction (XRD). The isothermal softening kinetics curves were determined for all samples. Discontinuous recrystallization and extended recovery are responsible for the softening of this alloy. The Johnson-Mehl-Avrami-Kolmogorov (JMAK) model was used to test our experimental data. The Avrami exponents (0.26≤n≤0.48) showed substantially smaller values than those predicted theoretically. This can be attributed to concurrent recovery and to a non-random distribution of recrystallization nuclei.




200.    Hurd, J. L., K. P. Rodbell, et al. (1994). "Local Texture and electromigration in fine line microelectronic aluminum metallization." MRS 343.




201.    Hurd, J. L., K. P. Rodbell, et al. (1998). "Linewidth and underlayer influence on texture in submicrometer-wide Al and AlCU lines." Applied Physics Letters 72(3).




202.    Hurley, P. J. and F. J. Humphreys (2002). "Characterising the deformed state in Al-0.1Mg alloy using high-resolution electron backscattered diffraction." Journal of Microscopy 205(3): 218-225.

The application of high resolution electron backscatter diffraction (EBSD) in a field emission gun scanning electron microscope to the characterization of a deformed aluminium alloy is discussed and the results are compared with those obtained by transmission electron microscopy. It is shown that the adequate spatial resolution, accompanied by the improvement in angular resolution to ~0.5° that can be achieved by data processing, together with the extensive quantitative data obtainable, make EBSD a suitable method for characterizing the cell or subgrain structures in deformed aluminium. The various methods of analysing EBSD data to obtain subgrain sizes are discussed and it is concluded that absolute subgrain reconstruction is the most accurate.




203.    Hurley, P. J. and F. J. Humphreys (2003). "The application of EBSD to the study of substructural development in a cold rolled single-phase aluminium alloy." Acta Materialia 51(4): 1087-1102.

Scanning electron microscopy and high resolution electron backscatter diffraction (EBSD) have been used to study substructural development during cold rolling of a single-phase Al-0.1 Mg alloy, the use of EBSD enabling more detailed quantitative measurements to be made than are possible with the transmission electron microscope (TEM). At low strains, bands of elongated cells, aligned at approximately 35 deg to rolling direction are formed. As the applied strain was increased, intersecting thinner and more widely spaced bands form within many grains, flow becomes localised within these new bands and they develop into microshear bands, which shear the original elongated cell structures. The changes in the scale of the microstructural features, the development of misorientations of the various types of low angle boundary and the alignment of the features to the rolling plane have been measured as a function of strain. The results are compared with previous TEM investigations of deformed aluminium, and a qualitative model of the microstructural evolution is proposed.




204.    Hurley, P. J. and F. J. Humphreys (2003). "Modelling the recrystallization of single-phase aluminium." Acta Materialia 51: 3779-3793.

An analytical mean field model of recrystallization by strain induced grain boundary migration (SIBM), based on cellular growth, has been implemented and compared to experimental measurements of a single-phase Al–0.1Mg alloy deformed to moderate strains. The model is able to predict the onset (nucleation) of primary recrystallization and the kinetics and grain size. Inputs to the model are the prior grain size and the subgrain parameters of the deformation microstructure, together with published values of boundary energies and mobilities. No other parameters are required. The predictions of grain size and recrystallization kinetics are found to be within ~25% of the measured values, and the effects of the limitations of the input data on the model are discussed. The work highlights the difficulties involved with implementing even the simplest physically based model of recrystallization, which are primarily related to problems in adequately characterizing the deformed state and inadequate knowledge of the energies and mobilities of boundaries. Improvements to the model including the incorporation of orientation (texture) dependent stored energies and crystallographic and geometric factors effecting boundary growth rates are discussed.




205.    Hurley, P. J. and F. J. Humphreys (2004). "A study of recrystallization in single-phase aluminium using in-situ annealing in the scanning electron microscope." Journal of Microscopy 213(Pt 3): 225-234.

In-situ annealing experiments were performed in the scanning electron microscope on a single-phase Al-0.13Mg alloy cold rolled to different strain levels. Once the validity of the technique had been verified by comparison of the recrystallization kinetics and final grain size with bulk annealed samples, the method was used in combination with electron back-scattered diffraction (EBSD) to study the potential mechanisms for recrystallization in this alloy. During annealing of material rolled to moderate strains (epsilont 60 0.7), the primary mechanism was strain-induced boundary migration (SIBM). In material rolled to higher true strains (epsilont > 1.4), recrystallization occurred extensively along pre-existing cube bands and EBSD measurements showed that the mean size of cells within the cube bands was larger than for all other orientations measured, suggesting a size advantage was responsible for the strengthening of cube texture during recrystallization. SIBM was shown to occur concurrently with the nucleation along cube bands but this contributed a lower proportion of nucleation sites during recrystallization.




206.    Hurley, P. J. and P. D. Hodgson (2001). "Formation of ultra-fine ferrite in hot rolled strip: potential mechanisms for grain refinement." Materials Science and Engineering A 302: 206-214.

A novel single-pass hot strip rolling process has been developed in which ultra-fine (< 2 mm) ferrite grains form at the surface of hot rolled strip in two low carbon steels with average austenite grain sizes above 200 µm. Two experiments were performed on strip that had been re-heated to 1250°C for 300 s and air-cooled to the rolling temperatures. The first involved hot rolling a sample of 0.09 wt.%C–1.68Mn–0.22Si–0.27Mo steel (steel A) at 800°C, which was just above the Ar3 of this sample, while the second involved hot rolling a sample of 0.11C–1.68Mn–0.22Si steel (steel B) at 675°C, which is just below the Ar3 temperature of the sample. After air cooling, the surface regions of strip of both steel A and B consisted of ultra- fine ferrite grains which had formed within the large austenite grains, while the central regions consisted of a bainitic microstructure. In the case of steel B, a network of allotriomorphic ferrite delineated the prior-austenite grain boundaries throughout the strip cross-section. Based on results from optical microscopy and scanning:transmission electron microscopy, as well as bulk X-ray texture analysis and microtextural analysis using Electron Back-Scattered Diffraction (EBSD), it is shown that the ultra-fine ferrite most likely forms by a process of rapid intragranular nucleation during, or immediately after, deformation. This process of inducing intragranular nucleation of ferrite by deformation is referred to as strain-induced transformation.




207.    Hurley, P. J., P. S. Bate, et al. (2003). "An objective study of substructural boundary alignment in aluminium." Acta Materialia 51(16): 4737-4750.

The alignment of substructure formed during deformation by rolling in Al-0.13%Mg has been investigated using electron back-scattered diffraction (EBSD). The substructure in this material was defined by walls of high dislocation content, which could be imaged as low-angle boundaries. Trace distributions of those boundaries were calculated using a local Radon transform image processing method, and the boundary normal distribution estimated using data from different sections. There was no evidence for alignment of the substructural boundaries with slip planes or any other simple crystallographic element, and it seems that the substructure is orientated primarily with respect to the macroscopic or mesoscopic straining state.




208.    Hutchinson, B. (1996). Microtextural Studies of Recrystallization. Eleventh International Conference on Textures of Materials, Xi'an, China, International Academic Publishers.




209.    Hutchinson, B., J. Oliver, et al. (2004). Whisker Growth from Tin Coatings. Second Joint International Conference on Recrystallization and Grain Growth, ReX & GG2, SF2M, Annecy, France, Trans Tech Publications Ltd.




210.    Hutchinson, B., L. Ryde, et al. (1998). "Texture in hot rolled austenite and resulting transformation produces." Materials Science and Engineering A257: 9-17.




211.    Hutchinson, W. B., E. Lindh, et al. (1999). On the determination of textures from discrete orientation measurements. Twelfth International Conference on Textures of Materials (ICOTOM 12), McGill University, Montreal, Canada, NRC Research Press.




212.    Hwang, B., H. S. Lee, et al. (2005). "Dynamic Deformation Behavior of Ultra Fine-Grained Low-Carbon Steels Fabricated by Equal-Channel Angular Pressing." Metallurgical and Materials Transactions A 36A(2): 389-397.

The dynamic deformation behavior of ultrafine-grained low-carbon steels fabricated by equal-channel angular pressing (ECAP) was investigated in this study. Dynamic torsional tests, using a torsional Kolsky bar, were conducted on four steel specimens, two of which were annealed at 480°C after ECAP, and then the test data were compared in terms of microstructures, tensile properties, and adiabatic shear-band formation. The equal-channel angular pressed specimen consisted of very fine, equiaxed grains of 0.2 to 0.3 μm in size, which were slightly coarsened after annealing. The dynamic torsional test results indicated that maximum shear stress decreased with increasing annealing time, whereas fracture shear strain increased. Some adiabatic shear bands were observed at the gage center of the dynamically deformed torsional specimen. Their width was smaller in the equal-channel angular pressed specimen than in the 1-hour-annealed specimen, but they were not found in the 24-hour-annealed specimen. Ultrafine, equiaxed grains of 0.05 to 0.2 μm in size were formed inside the adiabatic shear band, and their boundaries had characteristics of high-angle grain boundaries. These phenomena were explained by dynamic recrystallization due to a highly localized plastic strain and temperature rise during dynamic deformation.




213.    Hwang, B., Y. G. Kim, et al. (2004). "Analysis of Toughness and Transition Temperature of High-Toughness Pipeline Steels. I. Charpy Impact Properties and Effective Grain Sizes." Journal of the Korean Institute of Metals and Materials 42(9): 691-700.

This study is concerned with the effects of microstructure on Charpy V-notch (CVN) impact properties of a high-toughness API X70 pipeline steel. Six kinds of steel specimens were fabricated by varying hot-rolling conditions, and their microstructures and CVN properties were investigated. In addition, their effective grain sizes were characterized by the electron back-scatter diffraction (EBSD) analysis. The Charpy impact test results indicated that the specimens rolled in the single phase region had the higher upper shelf energy (USE) and the lower energy transition temperature (ETT) than the specimens rolled in the two phase region because their microstructures were composed of acicular ferrites and fine polygonal ferrites. The decreased ETT in the specimens rolled in the single phase region could be explained by the decrease in the overall effective grain size due to the presence of acicular ferrite having smaller effective grain size. On the other hand, CVN properties of the specimens rolled in the two phase region were deteriorated as they contained a small amount of martensites or cementites.




214.    Hwang, N.-M. (2004). New Understanding of Abnormal Grain Growth Approached by Solid-State Wetting along Grain Boundary or Triple Junction. Second Joint International Conference on Recrystallization and Grain Growth, ReX & GG2, SF2M, Annecy, France, Trans Tech Publications Ltd.




215.    Hwang, N.-M., H.-R. Jin, et al. (2006). "Abnormal grain growth of lead zirconium titanate (PZT) ceramics induced by the penetration twin." Journal of the American Ceramic Society 89(5): 1530-1533.

Lead zirconium titanate (PZT) ceramic specimens were prepared by liquid phase sintering with excess PbO. By the addition of a small amount of MgO, the grain shape was changed from spherical to angular. When SiO2 was further added, twin was induced in a few grains, which grew abnormally during heat treatment. Through the electron backscatter diffraction analysis and the observation of three-dimensional grain morphology, the abnormally grown large PZT grains were determined to be penetration twinned. Abnormal grain growth was suggested to be because of reentrant edges formed at the twinned grains. re. This 2006 The American Ceramic Society.




216.    Hwang, S.-K., S.-I. K. Kim, et al. (2003). "Evolution of dynamic recrystallisation in AISI 304 stainless steel." Materials Science and Technology 19(12): 1648-16452.

The nucleation and development of dynamic recrystallisation (DRX) has been studied via hot torsion testing of AISI 304 stainless steel. The DRX behaviour was investigated with microstructural analysis and slope changes of flow stress curves. The characteristics of serrated grain boundaries observed by SEM, electron backscattered diffraction and TEM indicated that the nucleated DRX grain size was similar to that of the bulged part of the original grain boundary. The DRX of the alloy was nucleated and developed by strain induced grain boundary migration and by the necklace mechanism. Before the steady state in the flow curve at 1000ens in or C and 0.5 s-1, the dynamically recrystallised grains did not remain a constant size and gradually grew to the size of fully DRX grains at steady state (30 µm). The calculation of the grain size was based on XDRX (volume fraction of dynamically recrystallisation) under the assumption that the nucleated DRX grains grow to the steady state continuously. It was found that the calculated grain size of the alloy was good agreement with that of the observed grain size. It is expected that a fine grained steel can be obtained by controlling hot deformation conditions on the basis of newly developed equations for predicting DRX behaviour.




216 records found

 

 

  
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