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123 records found
1.
Fairhurst, R. J., H.-Y. Zhai, et al. (2000). "Crystallographic study of
superconducting YBCO thin-films by EBSD." Physica C 341(NOV):
2019-2020.
Dot-mapping with EBSD allows an orientation image of the sample to be built
up, showing the orientation of individual grains, sub-grains, and twins.
This, combined with x-ray maps to indicate impurities, allows a particularly
full characterization of thin films. We have constructed an EBSD map of YBCO
thin film and measured the degrees of grain alignment in these materials.
Results show that the YBCO thin film studied has 98% c axis
alignment.
2.
Fan, A. L., W. H. Tian, et al. (2005). "Microstructural Characteristics
Associated with High-Strain-Rate Plastic Deformation in the Electroformed
Copper Liner of Shaped Charges." Acta Metallurgica Sinica 18(5):
620-626.
The microstructures of electroformed copper liners of shaped charges that
had undergone high-strain-rate deformation were observed by optical
microscopy (OM) and scanning electron microscopy (SEM). Meanwhile, the
orientation distribution of the grains in the recovered jet was examined by
electron backscattering Kikuchi pattern (EBSP) technique. EBSP analysis
reveals that the fibrous texture observed in the as-electroformed copper
liners disappeared after explosive detonation deformation. OM observation
shows that the microstructure evolves systematically from the jet center to
its perimeter during cooling from high temperatures after explosive
detonation deformation. This microstructural characteristic is similar to
that of solidification, i.e. there exist equiaxed grains in the center of
the jet and significant columnar grains around the equiaxed grains. The
result reveals that there is melting-related phenomenon in the jet center.
Corresponding microhardness variations from the jet center to its perimeter
is also determined. All the phenomena can be explained by a strong gradient
of temperature across the section of the jet during plastic deformation at
high-strain-rate.
3.
Fan, A., Q. Sun, et al. (2006). "Microstructure and penetration
behavior of electroformed copper liners of shaped charges during explosive
detonation deformation." Journal of University of Science and
Technology Beijing: Mineral Metallurgy Materials 13(1):
73-77.
The microstructure in the electroformed copper liners of shaped charges
prepared with different electrolytes was studied by scanning electron
microscopy (SEM) and electron backscattering Kikuchi pattern (EBSP) methods.
SEM observations revealed the existence of columnar grains in electroformed
copper liners of shaped charges formed by electrolyte without any additive
and the average grain size is about 3 µm. When an additive is
introduced to the electrolyte, the grains formed in the copper liners become
equiaxed and finer. EBSP results show that the columnar grain grown during
electroformation has the most preferential growth direction, whereas no
micro-texture exists in the specimen prepared by electrolyte with the
additive. Further, explosive detonation deformation experiments show that
penetration depth is dramatically improved when the electroformed copper
liners of shaped charges exhibit equiaxed grains.
4.
Fan, L., C. Pan, et al. (2005). "Structural transformation and grain
boundary character distribution during super high temperature service of
austenitic stainless steel analyzed by EBSD." Chinese Journal of
Stereology and Image Analysis 10(4): 233-236.
The microstructure transformation and grain boundary character distribution
of a YUS701 austenitic stainless steel ROF internal cover, which were
operated at very high temperatures, were investigated by using the electron
backscatter diffraction technique. Significant changes in microstructure and
grain boundary character distributions were observed, which are attributed
as the major cause for failure of the ROF internal cover due to very high
temperature service conditions.
5.
Fang, H., R. Naguib, et al. (2004). "Development of cube textured Ni-W
alloy tapes using powder metallurgy along with high energy ball milling for
HTS coated conductors." Superconductor Science and Technology
17(7): 947-953.
Ni based alloys have received considerable attention as the substrates for
HTS coated conductors due to improved mechanical properties and reduced
magnetization. Powder metallurgy is one of the promising processes for the
fabrication of long alloy textured substrates. In this paper, Ni-3 at.% W
alloy substrates were prepared by using high purity metal powders as
starting materials. The Ni and 3 at.% W powder mixture was high energy ball
milled for different periods, isostatically pressed, sintered, rolled and
texture annealed. The high energy ball milling process made the powders mix
uniformly and the grain sizes decrease significantly, which led to higher
boundary energy and residual strain energy. The longer ball milling period
resulted in a finer grain size and sharper texture in the substrate, which
were confirmed by EBSD and SEM analysis. SEM and AFM observations indicate
the surface of textured Ni-3 at.% W substrates is smooth and the roughness
value (Rrms) is about 1.126 nm, which is suitable for deposition
of buffer layers.
6.
Fang, Y., T. Fossier, et al. (2004). "Crack path simulation and
identification in polycrystalline alumina." Scripta Materialia
50: 127-130.
A transgranular crack is observed in polycrystalline alumina (Lucalox). By a
2-D calculation, it is proposed that surface crack propagation is dominated
by the grain cleavage plane rather than the high residual stresses from
processing.
7.
Farooq, M. U. (2005). "Use of EBSD Technique as a Means to Investigate
the Microstructure of Engineering Materials." DOKTORSAVHANDLINGAR-
CHALMERS TEKNISKA HOGSKOLA 2398.
8.
Farooq, M. U. and U. Klement (2004). "EBSD characterization of
carbide-carbide boundaries in WC-Co composites." Journal of Microscopy
213(Pt 3): 306-312.
A sample of WC-6wt%Co was investigated for grain boundary character
distribution and occurrence of coincidence site lattice (CSL) boundaries on
a statistical basis. For this purpose orientation measurements of the grains
were carried out using electron back-scattered diffraction (EBSD). The
dominant misorientation relationships were determined by complementary EBSD
data representation tools such as orientation maps, misorientation angle
distribution histograms and the sectioned three-dimensional misorientation
space. It was found that the grain boundary character distribution of the
material is nearly random and the CSL boundaries are not present in
statistically significant amounts. It was also found that the amount of
binder phase does not play a role in the formation of special boundaries.
The paper focuses on the methodology of characterizing grain boundaries in a
hexagonal material using EBSD
9.
Farrer, J. K., C. Barry Carter, et al. (2006). "The effects of
crystallography on grain-boundary migration in alumina." Journal of
Materials Science 41(3): 661-674.
The sintering process of ceramics involves mass transport across grain
boundaries resulting in the migration of these boundaries. When there is a
liquid at the interface-as in liquid-phase sintering-the mass transport can
be enhanced. In this study, electron backscatter diffraction has been used
to examine grain-boundary migration of controlled interfaces in alumina. The
interfaces were prepared by hot pressing single-crystal and polycrystalline
alumina to single-crystal alumina substrates of known orientation. EBSD
patterns, taken near the sintered interfaces, have been used to study the
effects of crystallography on migration direction and rate.
10.
Farrer, J. K., J. R. Michael, et al. (2000). EBSD of Ceramic Materials.
Electron Backscatter Diffraction in Materials Science. A. J. Schwartz, M.
Kumar and B. L. Adams. New York, Kluwer Academic/Plenum Publishers:
299-316.
11.
Farrer, J. K., M. C. Chipman, et al. (2002). EBSD Performed
“In-Situ” on a Dual-Beam FIB. Microscopy and Microanalysis 2002,
Québec City, Québec, Canada, Cambridge University
Press.
12.
Farrer, J. K., N. Ravishankar, et al. (2001). Study of Grain Boundary
Migration in Alumina. The Fourth Pacific Rim International Conference on
Advanced Materials and Processing (PRICM4).
The sintering process of ceramics involves mass transport across grain
boundaries resulting in the migration of these boundaries. When there is a
liquid at the interface - as in liquid-phase sintering - the mass transport
can be enhanced. In this study, electron backscatter diffraction (EBSD) has
been used to examine grain-boundary migration (GBM) of controlled interfaces
in alumina. The interfaces were prepared by liquid-phase sintering
single-crystal and polycrystalline alumina to single crystal substrates of
known orientation. EBSD patterns, taken near the sintered interfaces, have
been used to study the effects of crystallography on GBM and to study the
orientation relationships within the migrated regions. Results indicate that
migration of the controlled interfaces occurs only when the bounding planes
are different, and that the direction of migration is not always the same as
that predicted by the current theories on GBM.
13.
Faryna, M. (2003). "Study on the non-linear property of abnormally
grown grain ZnO." Materials Chemistry and Physics 81(2-3):
301-304.
Transmission electron microscopy and electron backscatter diffraction in the
scanning electron microscope have been used to investigate particulate
composites with the tetragonal zirconia polycrystalline (TZP) matrix. Two
carbides, mainly TaC and NbC, chemically stable in relation to zirconia,
have been selected as reinforcing inclusions. Their incorporation into the
TZP matrix resulted in significantly better mechanical properties of the
investigated systems. The way of explaining such a phenomenon is to analyze
the crystallographic correlations between the oxide and carbide phases which
may influence the strength of the interphase boundary and finally lead to an
increase of fracture toughness and wear resistance of the composite.
14.
Faryna, M. (2003). "TEM and EBSD comparative studies of
oxide–carbide composites." Materials Chemistry and Physics
81: 301-304.
Transmission electron microscopy and electron backscatter diffraction in the
scanning electron microscope have been used to investigate particulate
composites with the tetragonal zirconia polycrystalline (TZP) matrix. Two
carbides, mainly TaC and NbC, chemically stable in relation to zirconia,
have been selected as reinforcing inclusions. Their incorporation into the
TZP matrix resulted in significantly better mechanical properties of the
investigated systems. The way of explaining such a phenomenon is to analyze
the crystallographic correlations between the oxide and carbide phases which
may influence the strength of the interphase boundary and finally lead to an
increase of fracture toughness and wear resistance of the composite.
15.
Faryna, M., E. Bischoff, et al. (2002). "Crystal Orientation Mapping
Applied to the Y-TZP/WC Composite." Mikrochimica Acta 139:
55-59.
16.
Faryna, M., J. Jura, et al. (2000). "Orientation Imaging Microscopy
Applied to Zirconia Ceramics." Mikrochimica Acta 132(2-4):
517-520.
Measurements of crystallographic orientations along with microscopic
observations are the basis of quantitative investigations of the
microstructure of crystalline materials. The technique that applies
automatic orientation measurements in the transmission or scanning electron
microscope is known as orientation imaging microscopy (OIM) [1]. In this
paper the measurements and analyses of sets of single orientations gained
from electron backscattered diffraction (EBSD) registered in a scanning
electron microscope are presented. A quantitative description of
microstructure of two polymorphs of zirconia, based on measurements of
single orientations, is also given.
17.
Faryna, M., W. Wolczynski, et al. (2002). "Microanalytical Techniques
Applied to Phase Identification and Measurement of Solute Redistribution at
the Solid/Liquid Interface of Frozen Fe-4.3Ni Doublets." Mikrochimica
Acta 139: 61-65.
18.
Faul, U. H. and J. D. FitzGerald (1999). "Grain misorientations in
partially molten olivine aggregates: an electron backscatter diffraction
study." Physics and Chemistry of Minerals 26(3):
187-197.
In polycrystalline aggregates of olivine with mean grain sizes above 35
µm plus a low basaltic melt fraction, both wetted and melt-free grain
boundaries are observed after equilibration times at high pressures and
temperatures of between 15 and 25 days. In order to assess a possible
dependence of the wetting behaviour on the relative orientation of
neighbouring grains, a SEM based technique, electron backscatter diffraction
(EBSD), is used to determine grain orientations. From the grain orientations
relative orientations of neighbouring grains are calculated, which are
expressed as misorientation axis/angle pairs. The distribution of
misorientation angles and axes of melt-free grain boundaries differ
significantly from a purely random distribution, whereas those of wetted
grain boundaries are statistically indistinguishable from the random
distribution. The relative orientation of two neighbouring grains therefore
influences the character of their common grain boundary. However, no
clustering towards special (coincident site lattice) misorientation axes is
observed, with the inference that the energy differences between special and
general misorientations are too small to lead to the development of
preferred misorientations during grain growth.
19.
Feldmann, D. M., D. C. Larbalestier, et al. (2005). "Evidence for
extensive grain boundary meander and overgrowth of substrate grain
boundaries in high critical current density ex situ
YBa2Cu3O7-x, coated conductors."
Journal of Materials Research 20(8): 2012-2020.
It has been generally accepted that
YBa2Cu3O7-x (YBCO) films deposited on
deformation textured polycrystalline metal tapes result in YBCO grain
boundary (GB) networks that essentially replicate the GBs of the underlying
substrate. Here we report that for thicker YBCO films produced by a
BaF2 ex situ process, this is not true. Using electron
backscatter diffraction combined with ion milling, we have been able to map
the evolution of the YBCO grain structure and compare it to the underlying
template in several coated conductors. For thin (<or=0.5 µm) YBCO
films deposited on rolling-assisted biaxially textured substrates (RABiTS),
the YBCO GBs nearly directly overlap the substrate GBs. For 0.7-1.4 µm
YBCO films, the GBs were found to meander along the substrate GBs and along
the sample normal, with displacements several times the film thickness. In
very thick films (2.5-2.9 µm), the YBCO grains can completely overgrow
substrate grains and GBs, resulting in a substantial disconnection of the
YBCO and substrate GB networks. Similar behavior is found for
BaF2 ex situ YBCO films on ion-beam-assisted deposition-type
templates. The ability of the YBCO to overgrow substrate grains and GBs is
believed to be due to liquid-phase mediated laminar grain growth. Although
the behavior of the YBCO GB networks changes with YBCO film thickness, the
samples maintained high critical current density (Jc) values of
>2 MA/cm2 for films up to 1.4 µm thick, and up to 0.9
MA/cm2 for 2.5-2.9- µm-thick films.
20.
Feng, H., H. Zhu, et al. (2005). Microstructure and Texture in Free-standing
CVD Diamond Films. Textures of Materials - ICOTOM 14, Leuven, Belgium, Trans
Tech Publications.
Free-standing CVD diamond films were prepared under the substrate
temperature in the range of 850-1050°C. Macro- and micro-textures of the
films were investigated based on the SEM observation as well as on the ODF
and EBSD analysis. It was found that certain growth selection process
appeared during diamond deposition which, however, did not lead to a strong
film texture. It is indicated that strong fluctuation of growth ratio
V<100>/V<111> and frequent growth twinning
during film deposition resulted in randomization effect of grain
orientations, which can be transformed by adjusting the parameters of film
preparation.
21.
Feng, H., Y. Zhou, et al. (2005). "Microstructural Characterization of
Spark Plasma Sintered In Situ TiB Reinforced Ti Matrix Composite by EBSD and
TEM." Materials Transactions 46(3): 575-580.
The spark plasma sintered in situ TiB reinforced titanium metal matrix
composite was investigated by EBSD and TEM. The sintered composite consists
of 30.8% α-Ti phase, 55.7% β -Ti phase and 12.9% in situ TiB
reinforcements. Most of the TiB whiskers distributed along phase boundaries
between a-Ti and β-Ti, others located within α-Ti and β-Ti
grains. Some b-Ti grains with parallel TiB whiskers were observed in the
orientation imaging micrograph (OIM). The TiB grows along 010 direction and
forms whisker with a hexagonal cross-section. The 010 direction of
paralleled TiB whiskers is parallel to 111 direction of cubic β-Ti.
High density stacking faults are formed in (100)TiB planes to minimizing the
lattice mismatch between TiB and the Ti matrix.
22.
Fernández, L., B. Holzapfel, et al. (2002). "Grain boundary
network transport properties of
YBa2Cu3O7film on biaxially textured metal
substrates." Physica C 372-376: 656-658.
YBa2Cu3O7 films have been grown epitaxially
on biaxially textured Ni substrates and on single crystalline Ni films by
laser ablation. The configuration of the samples was
YBa2Cu3O7/yttrium-stabilized
zirconia/CeO2/Ni in both cases. The
YBa2Cu3O7 coated conductor sample shows due
to the grain boundary network (GBN) a reduced Jc value of 0.3
MA/cm2 (T= 77 K and B = 0 T) compared with the Jc
corresponding to the sample on the single crystalline Ni film of 1.3
MA/cm2 (T = 77 K and B = 0 T). Texture and electron
backscattering diffraction measurements of the samples were performed before
and after the growth; this allowed a quantitative evaluation of the average
misorientation of the GBN, which determines the critical current
density.
23.
Fernandes, J. V. and J. H. Schmitt (1983). "Dislocation Microstructures
in Steel During Deep Drawing." Philosophical Magazine A 48(6):
841-870.
24.
Ferre, E. C., B. Tikoff, et al. (2005). "The magnetic anisotropy of
mantle peridotites: Example from the Twin Sisters dunite, Washington."
Tectonophysics 398(3-4): 141-166.
The Twin Sisters dunite massif, Washington State, provides unweathered
peridotites for magnetic analysis. These rocks have been chosen to test a
new magnetic fabric based on measuring the anisotropy of magnetic
susceptibility (AMS) in high-field with a vibrating sample magnetometer.
Although the dunites are fresh, they host small quantities of secondary
magnetite formed along cracks. Under low-field conditions magnetite masks
the magnetic fabric of olivine, and thus the magnetic fabric does not
reflect mantle flow deformation. Above the magnetic saturation, at a field
of 1 T, the ferrimagnetic component is removed and the high-field slope
represents the paramagnetic AMS only. This high-field AMS originates from
the magnetocrystalline anisotropy of olivine. The high-field AMS are
compared with lattice preferred orientation (LPO) fabric data obtained by
electron backscatter diffraction. LPO point distributions are formed by
high-temperature plastic flow, and match the high-field measurements. In
contrast, girdle LPOs present notable departures from the high-field AMS
axes.
25.
Ferrer, J. P., C. Capdevila, et al. (2005). Influence of Finishing Rolling
Temperature on Recrystallization of Electrical Steels. Solid to Solid Phase
Transformations in Inorganic Materials 2005, Phoenix, Arizona, USA,
TMS.
This paper deals with the influence of finishing rolling temperature (FRT)
of hot rolling on recrystallization processes during subsequent reheating at
temperatures ranging between 800 and 950°C on two electrical steels with
different silicon content (1.3 and 0.3 wt.-%). EBSD analysis together with
thermoelectric power measurements and metallographic analysis have shown an
interaction between precipitation and recrystallization leading to
microstructures formed by coarse grains.
26.
Ferry, M. (2002). Mechanism of Discontinuous Subgrain Growth in As-Deformed
Aluminium Single Crystals. ICOTOM 13, Seoul, Korea, Trans Tech Publications
Inc.
Recent experimental and theoretical work has confirmed that, under certain
processing conditions, discontinuous subgrain growth (DSG) occurs in
deformed high stacking fault energy alloys such as aluminum, nickel and
iron. It was shown that, during annealing, a small number of subgrains grow
rapidly to consume the surrounding substructure in a manner analogous to
secondary recrystallization. This phenomenon was attributed to the
orientation dependence of low angle boundary energies and mobilities. In the
present work, {110}<001>-oriented aluminum single crystals were
deformed in plane strain compression (PSC) and lightly annealed to study the
origin of DSG using TEM and SEM/EBSD. It was found that, while the
{110}<001> orientation is predicted to be highly stable during PSC,
deformation was not as uniform on a microscale with the development of
localized regions of microstructure exhibiting a large spread in subgrain
orientations. TEM evidence indicates that deformation does not occur
uniformly on all four of the active slip systems in this crystal, but may
occur by a combination of single and coplanar slip to produce orientation
perturbations throughout the microstructure. These locally perturbed regions
are argued to be favorable sites for rapid growth of subgrains, which is
consistent with the proposed conditions for DSG in the earlier work.
27.
Ferry, M. (2005). "Influence of fine particles on grain coarsening
within an orientation gradien." Acta Materialia 53:
773-783.
A simple model of grain coarsening is presented that takes into account the
influence of both an orientation gradient within the microstructure and a
dispersion of fine particles on the kinetics of grain coarsening. The model
is used to illustrate the substantial influence of fine particles on grain
coarsening whereby, in a particle-free system, grains within a large
orientation gradient grow rapidly whereas a system containing a large volume
fraction of fine particles results in very limited coarsening, despite the
presence of the orientation gradient. The model is used in conjunction with
the analysis of grain coarsening in some aluminium alloys where deformation
was found to generate a range of microstructural inhomogeneities such as
either deformation bands in hot deformed {100}fi001fi Al–0.05%Si
single crystals or a microstructure consisting of colonies of either low
angle or high angle grain boundaries in a severely strained particle-
containing Al–0.2%Sc alloy. The simulations using the model are found
to be in broad agreement with the experimental observations of grain
coarsening in these alloy systems.
28.
Ferry, M. (2005). Uniformity of grain coarsening in a submicron grained
Al-Sc alloy containing local variations in texture. Textures of Materials -
ICOTOM 14, Leuven, Belgium, Trans Tech Publications.
The effect of fine particles on the uniformity of grain coarsening in a
submicron grained Al-Sc alloy containing significant local variations in
texture has been investigated using high resolution EBSD. The alloy was
processed by severe plastic deformation and low temperature ageing to
generate a fine-grained (0.8 μm diameter) microstructure containing
either a dispersion of nanosized Al3Sc particles or a
particle-free matrix. The initial processing generated a uniform grain size
distribution, but the distribution of grain orientations was inhomogeneous
with the microstructure containing colonies of grains consisting
predominantly of either HAGBs or LAGBs with the latter possessing
orientation gradients of up to 10 o/μm. Despite the marked differences
in boundary character between these regions, the alloy undergoes slow and
uniform grain coarsening during annealing at temperatures up to 500°C
with no marked change in the grain size distribution, boundary distribution
and texture. A model of grain coarsening that takes into account the
influence of fine particles on the kinetics of grain growth within an
orientation gradient is outlined. The model predicts that a large volume
fraction of fine particles (large f/r-value) tends to homogenize the overall
rate of grain coarsening despite the presence of orientation gradients in
the microstructure.
29.
Ferry, M. and A. Hunter (2002). Factors Affecting the <001> Fiber
Texture in Strip-Cast Stainless Steels. ICOTOM 13, Seoul, Korea, Trans Tech
Publications Inc.
The solidification behaviour of an austenitic and ferritic stainless steel
(~1 mm gauge) strips were studied using a melt-substrate contacting
apparatus. The effect of alloy type and casting conditions (substrate
topography and melt superheat) on the development of microstructure and
texture during solidification was studied using EBSD and optical microscopy.
The steels solidified to produce either a ferritic or austenitic matrix with
a distribution of one or more second phases. Randomly-oriented grains
nucleated at the chill surface and further solidification resulted in the
preferred growth of <001>-oriented grains perpendicular to the
substrate wall to produce a coarse columnar grain structure and and a
strengthening of the <001> fibre texture. Regardless of alloy and
casting conditions, there was a natural tendency for both steels to develop
this fibre texture; a texture component detrimental to sheet formability.
The results indicate that secondary processing may be necessary to produce
more formable stainless steel sheet by strip casting.
30.
Ferry, M. and F. J. Humphreys (2005). A study of the early stages of
recovery in cold rolled {110}<001> oriented copper single crystals.
Textures of Materials - ICOTOM 14, Leuven, Belgium, Trans Tech
Publications.
Copper single crystals of {110}<001> crystallographic orientation were
cold rolled to a true strain of 1.4. Specimens were cut from the as-deformed
crystals with all surfaces mechanically ground and deep-etched in
concentrated nitric acid to minimise the likelihood of surface nucleation of
recrystallized grains during subsequent annealing. The early stages of
static recovery were studied by annealing specimens at 300°C. The
crystallographic features of the deformed and annealed microstructures were
determined by high resolution electron backscatter diffraction. It was
observed that deformation was homogeneous with the microstructure in ND-RD
plane exhibiting two complementary sets of intersecting bands at ~±
35° to ND. Along these bands and in the microstructure, in general,
there was an overall spread in orientation about ND towards
{110}<112>. However, the orientation spread along these bands was
cyclic, that is, sinusoidal orientation gradients were generated about ND
with amplitude of up to 20° and wavelength 5-10 μm. Annealing
resulted in the preferred growth of cells that have orientations at the edge
of the orientation spread of the deformation substructure. This localized
coarsening of the microstructure is similar to the discontinuous subgrain
growth observed in {110}<001> oriented Al single crystals and
indicates that discontinuous subgrain (cellular) growth can also occur in
metals of lower stacking fault energy.
31.
Ferry, M. and N. E. Hamilton (2004). "Grain growth in a nanocrystalline
Al-Sc alloy." Materials Transactions 45(7): 2264-2271.
A sub-micron grained microstructure in an Al-0.2mass% 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 be highly stable during annealing at temperatures up to 500
degrees 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, Rc, in the Al-Sc alloy may
reasonably be predicted by the relation: Rc = 0.17r/f. This
relation is known to be applicable for coarse-grained alloys (>1
µm) and indicates its validity for predicting the limiting grain size
in sub-micron, particle-containing alloys.
32.
Ferry, M. and W. Xu (2004). "Microstructural and crystallographic
features of ausferrite in as-cast gray iron." Materials
Characterization 53(1): 43-49.
Ausferrite has been shown to form during casting of gray iron by carefully
controlling the alloying additions Mo, Mn, Si and Cu and consists of an
acicular ferrite constituent, termed bainitic ferrite (αB),
which develops during continuous cooling as a coarse, feathery-type
structure within the prior austenite (γ) grains. Regardless of alloy
composition, the ausferrite that forms in the microstructure during casting
in volume fractions greater than ~0.1 was found to have a constant bainitic
ferrite/retained austenite ratio (αB/γ3). Electron
backscatter diffraction (EBSD) in the scanning electron microscope has
demonstrated that αB and g in ausferrite is related by the
Kurdjumov–Sachs orientation relationship: 111 γ// 011
α and <011>γ//<
;111>α with a number of aB variants
possible within a given austenite grain. This study confirms that the
ausferrite generated in gray iron by direct casting has comparable
microstructural and crystallographic characteristics to that produced in
austempered gray and ductile irons.
33.
Ferry, M., N. E. Hamilton, et al. (2005). "Continuous and discontinuous
grain coarsening in a fine-grained particle-containing Al-Sc alloy."
Acta Materialia 53(4): 1097-1109.
An Al-0.2 wt% Sc alloy was solution treated, deformed by equal channel
angular pressing (ECAP) to an effective true strain of 9.2 then aged for 3 h
at 350 degrees C to produce a fine-grained (0.8 µm diameter)
microstructure containing a large fraction (similar to 0.7) of high angle
grain boundaries (HAGBs). This ageing treatment also generated a relatively
uniform dispersion of 5 nm diameter Al3Sc particles. Grain
stability was investigated at temperatures up to 550 degrees C using SEM,
EBSD and TEM. It was found that the fine-grain structure was remarkably
stable at temperatures up to 500 degrees C with grain coarsening occurring
gradually with no marked change in the grain size distribution, texture and
grain boundary character. This homogeneous coarsening behaviour is usually
termed continuous recrystallization. In this regime, both the fine-grained
microstructure and Al3Sc particles exhibit third order coarsening
kinetics with dR/dt. $VAR dr/dt which indicates that grain coarsening is
controlled by the rate of particle growth with the latter controlled by bulk
diffusion of scandium in the Al matrix. During extended annealing at 500
degrees C and for short times at higher temperatures, there is a notable
transition from continuous to discontinuous grain coarsening whereby a small
number of grains grow rapidly to produce a coarse (>10 µm) grain
size. An analytical mean field model of grain coarsening in
particle-containing alloys was shown to adequately predict this transition
in coarsening behaviour. Copyright 2004 Acta Materialia Inc. Published by
Elsevier Ltd. All rights reserved.
34.
Field, D. P. (1995). "On the Asymmetric Domain of Cubic
Misorientations." Scripta Metallurgica et Materialia 32(1):
67-70.
35.
Field, D. P. (1995). "Quantification of Partially Recrystallized
Polycrystals Using Electron Backscatter Diffraction." Materials Science
and Engineering A 190(1-2): 241-246.
36.
Field, D. P. (1997). "Recent advances in the application of orientation
imaging." Ultramicroscopy 67(1-4): 1-9.
Since the mid-1980s, electron back-scatter diffraction (EBSD, also known as
back-scatter Kikuchi diffraction, BKD) has become a well-known and often
used technique for interrogating the local characteristics of
microstructures. The more recent development of orientation imaging
microscopy (OIM) has led to the practical application of EBSD in obtaining
statistically relevant information from bulk materials. Many new
developments in OIM technology have evolved recently. One of these is the
development of rapid and more reliable mapping of multi-phase alloys. In
addition, significant work has been performed on thin film structures
including patterned films and integrated circuits for investigation of
texture evolution, grain growth, and circuit reliability. An additional
example showing the application of OIM on rough surface specimens, such as
fracture surfaces, is discussed.
37.
Field, D. P. (1999). QC for IC Interconnects? Vacuum and Thin Film:
36-40.
Orientation imaging microscopy (OIM) has rapidly become a standard
analytical technique in hundreds of research facilities throughout the
world. OIM is an electron diffraction-based technique which performs
crystallographic mapping of virtually any crystalline or polycrystalline
surface. It is an accessory that can be added to all scanning electron
microscopes given port availability. Over the past three or four years, OIM
has been used for addressing the problems of stress voiding and
electromigration of IC interconnect lines. It was shown that OIM is
effective in simultaneously measuring crystallographic texture and grain
size distributions in both blamket films and patterned wafers. Some
researchers suggest that at-line quality control of microstructural
parameters could be easily performed using OIM. In addition, OIM
canaccurately measure the grain boundary character distribution and identify
positions and distributions of low energy (both low angle and
"special") boundaries which are claimed to be resistant to
electromigration processes. These types of microstructural measures could
feasibly become standard parameters for quality control in future
generations of interconnect lines.
38.
Field, D. P. (1999). Texture evolution in Cu damascene lines. Twelfth
International Conference on Textures of Materials (ICOTOM 12), McGill
University, Montreal, Canada, NRC Research Press.
39.
Field, D. P. (2004). Textured Structures. Metallurgy and Microstructures. G.
F. Vander Voort. Materials Park, Ohio, ASM International. 9:
215-226.
40.
Field, D. P. and B. L. Adams (1990). "Unrecoverable Strain Hardening in
Torsionally Strained OFHC Copper." Journal of Engineering Materials and
Technology 112: 315.
41.
Field, D. P. and B. L. Adams (1992). "Heterogeneity of Intergranular
Damage in OFE Copper Crept in Plane-Strain Tension." Metallurgical
Transactions A 23(9): 2515-2526.
42.
Field, D. P. and B. L. Adams (1992). "Interface Cavitation Damage in
Polycrystalline Copper." Acta Metallurgica et Materialia 40(6):
1145-1157.
43.
Field, D. P. and B. L. Adams (1992). "Measurement of Interface Damage
Heterogeneity." Textures and Microstructures 20: 217-30.
44.
Field, D. P. and C. A. Michaluk (2000). Analysis of Texture Gradients in Ta
Sputtering Targets. Thermec 2000, Las Vegas, Nevada, USA, Elsevier Science
Ltd.
Tantalum has emerged as the material of choice for barrier layers used in
the copper damascene fabrication process of integrated circuit
interconnects. Reactive sputtering of high-purity Ta targets is typically
performed to deposit a thin film of TaN that serves as the barrier layer for
the Cu conductor. The sputtering performance of Ta targets is dependent upon
the crystallographic texture of the bombarded surface and sputtering yields
vary dramatically as a function of crystallite lattice orientation. As has
been well documented, Ta deforms heterogeneously and significant
through-thickness texture gradients typically exist in deformed plates.
These gradients are generally present in the microstructures of the targets.
Measurement of through-thickness texture gradients can be made using
orientation imaging techniques. An algorithm that takes into account the
point-to-point variation in texture, as well as the overall distribution,
facilitates quantification of these gradients. The values obtained through
this technique correlate directly with sputtering performance and can be
used as quality control parameters for target material. Control of the
gradients through tailored processing is discussed
45.
Field, D. P. and D. J. Dingley (1995). Microtexture Analysis in Aluminum
Thin Films by Orientation Imaging Microscopy. Solid State Technology:
91-96.
46.
Field, D. P. and D. J. Dingley (1996). Analysis of Grain Boundary Structure
in Aluminum Thin Films by Orientation Imaging Microscopy. 8th International
Conference of Japanese Institute of Metals, Toyama Japan.
47.
Field, D. P. and D. J. Dingley (1996). Method and Apparatus for Determining
Crystallographic Characteristics in Response to Confidence Factors. USA,
TexSEM Laboratories, Inc., Provo, Utah: 13.
An apparatus for determining the reliability of crystallographic solutions
for a specimen includes an electron beam generator, a stage for holding the
specimen, an image collection system for obtaining diffraction images of the
crystals within the specimen, and processor for processing the diffraction
images to obtain most promising inxdexing solutions for the crystals and to
generate confidence factors associated with the most probable indexing
solutions. The apparatus may utilize the confidence factors to determine the
phase of the crystals within the specimen. The confidence factors may also
be incorporated into reports representing the statistical confidence of
various crystallographic characteristics of the specimen.
48.
Field, D. P. and D. J. Dingley (1996). "Microstructure Mapping of
Interconnects by Orientation Imaging Microscopy." Journal of Electronic
Materials 25(11): 1767-1771.
Orientation Imaging Microscopy (OIM) provides a detailed description of the
variation in crystallographic structure over the surface of a single crystal
or polycrystalline bulk materials. This technique has been used in the
investigation of interconnect lines and contact pad material in a number of
aluminum metallizations of silicon oxide/silicon substrates. The specimens
were examined in a SEM fitted with apparatue for collecting electron
back-scatter diffraction patterns (EBSPs). OIM scans were performed over
various regions of each specimen. The technique has provided information
regarding the local texture variations between different regions of a thin
film structure for both patterned and unpatterned metallizations. It was
concluded that significant modification of the microstructure may occur
subsequent to the initial metal deposition and that this modification can
differ between the unpatterned regions and interconnect lines of varying
widths.
49.
Field, D. P. and D. P. Weiland (1994). The Dependence of Disloaction Density
and Cell Size on Crystallographic Orientation in Aluminum. Tenth
International Conference on Textures of Materials (ICOTOM 10), Clausthal,
Germany, Materials Science Forum.
50.
Field, D. P. and H. Weiland (2000). Characterization of Deformed
Microstructures. Electron Backscatter Diffraction in Materials Science. A.
J. Schwartz, M. Kumar and B. L. Adams. New York, Kluwer Academic/Plenum
Publishers: 199-210.
51.
Field, D. P. and M. M. Nowell (1999). Recrystallization and Growth of Pure
Cu Damascene Structures. 4th International Conference on Recrystallization
and Related Phenomena, Toyama Japan, Japanese Institute of Metals.
The push to increase integrated cicuit (IC) performance and reduce
electromigration effects has led to the implementation of Cu instead of Al
alloys in upper level interconnects. The damscene process or
"line-in-trench" fabrication technique is typically employed for
Cu structures. While known to be important to IC performance, the grain
morphology and crystallographic texture evolution of such structures is not
well understood. Cu lines tend to recrystallize at room temperature within
the first few days after fabrication. The present work investigates elevated
temperature recrystallization and growth of in-line Cu structures subsequent
to room temperature structure evolution. In-situ heating in conjunction with
conventional SEM imaging and orientation imaging techniques were employed in
the investigation to observe recrystallization and growth in Cu damascene
lines.
52.
Field, D. P. and T. W. Nelson (2002). Tool Geometry Dependence of Local
Texture in Friction Stir Welds of 7050 Aluminum Plate. ICOTOM 13, Seoul,
Korea, Trans Tech Publications Inc.
Friction stir welding employs tortuous thermomechanical deformation during
solid state joining of materials. The severe textural heterogeneity both
across the width and through the thickness of the weld nugget and
surrounding regions has been previously reported. Much of the research into
friction stir welding processes involves optimization of tool geometry. The
present work investigates the character of crystallographic textures as a
function of tool geometry. Three tool geometries are employed: a standard
threaded pin, a non-threaded pin, and a coarse threaded pin. The gradients
persist for the threaded weld tools but are significantly diminished with
the non-threaded tool. Important differences exist in the structures that
are discussed in relation to suspected material flow during friction stir
joining.
53.
Field, D. P., B. L. Adams, et al. (1991). "Analysis of Grain Boundary
Cavitation Damage in Copper." Textures and Microstructures
14-18: 977-982.
54.
Field, D. P., B. W. True, et al. (2003). "Observation of twin boundary
migration in copper during deformation." Materials Science and
Engineering A 372: 173-179.
A previous investigation produced evidence that twin boundaries in annealed
copper were a significant source of dislocations during the initial stages
of plastic flow. The character of the dislocation source was unknown, but it
was hypothesized that twin boundaries could be non-regenerative dislocation
sources that would cause migration of the boundary during plastic
deformation. Channel die deformation and intermittent orientation imaging
were performed on split specimens of pure copper in an attempt to observe
twin boundary migration. Approximately 15% of the twin boundaries were
observed to migrate beyond that expected from the imposed strain. The data
support the hypothesis that twin boundaries can serve as dislocation
sources.
55.
Field, D. P., D. Dornisch, et al. (2001). "Investigating the
micro-structure-reliability relationship in Cu damascene lines."
Scripta Materialia 45(9): 1069-75.
56.
Field, D. P., D. J. Dingley, et al. (1995). Analysis of Grain Boundary
Structure in Aluminum Thin Films by Orientation Imaging Microscopy. The 21st
International Symposium for Testing and Failure Analysis (ISTFA 21).
57.
Field, D. P., D. J. Dingley, et al. (1996). Orientation Imaging Microscopy
for Materials Research. Japan Institute of Metals - Texture Symposium,
Tokyo, Japan.
58.
Field, D. P., D. P. Nelson, et al. (1995). An Experimental Investigation of
Grain Boundary Structure Effects on Grain Growth. 2nd International
Conference on Grain Growth, Kitakuyshu, Japan.
59.
Field, D. P., H. L. Grohman, et al. (2004). "Factors affecting the
sputtering performance of magnetic materials." JOM 56(11):
210.
Effects of Si addition on the microstructure and magnetic D.C. magnetron
sputtering relies on a magnetic field usually imparted by a fixed or
rotating permanent magnet located behind the sputtering target, to trap free
electrons within the plasma. The spiral trajectory of the contained
electrons acts to increases the frequency of collisions with gaseous atoms,
subsequently increasing the density of the plasma and the sputtering
efficiency of the system. However, the magnetron sputtering of magnetic
metals and alloys present unique challenges; the target's low magnetic
permeability significantly hinders the magnetic flux from the permanent
magnet to the plasma. This paper reviews how a combination of texture
control and innovative target design is employed to enhance the sputtering
performance of magnetic materials. Recently developed data revealing the
correlation between global texture, characterized by Electron Backscatter
Diffraction (EBSD) and the Pass. Through Flux (PTF) of a Co-4.5Zr-4.5Ta
(CZT) alloy is also presented.
60.
Field, D. P., H. Weiland, et al. (1995). "Intergranular Cracking in
Aluminum Alloys." Canadian Metallurgical Quarterly 34(3):
203-210.
Intergranular cracking of aluminum alloys occurs by a variety of processes
in a host of structural components. Cracks emanate from holes and corners of
support structures and heterogeneously spread along grain boundaries. In the
present study, cracked specimens were investigated using local orientation
measurement techniques. True representation of grain boundaries in spaces of
five or eight dimensions was emphasized in characterizing the
microstructure. Orientation of the grain boundary plane with respect to the
stress axis and with respect to the crystal lattice was found to play an
important role in determining GB "specialness" in addition to
misorientation of the crystalline lattices.
61.
Field, D. P., H. Weiland, et al. (1999). Imaging dislocation cell morphology
in the SEM. The Integration of Material Process and Product Design. N.
Zabaras, R. Becker, L. Lalli and S. Ghosh. Rotterdam, Balkema:
27-32.
62.
Field, D. P., J. E. Sanchez, et al. (2005). Texture Evolution in Thin Cu
Films and Lines. Textures of Materials - ICOTOM 14, Leuven, Belgium, Trans
Tech Publications.
The shift in strategy from Al to Cu interconnects and from conventional
metal etching to a damascene, or in-laid, metal fabrication technique
presents new challenges to understand how manufacturing conditions control
the microstructure of copper interconnect features. The final microstructure
of inlaid copper interconnects forms within the confined space of the
pre-patterned dielectric, rather than within a 2- dimensional thin film.
Epitaxial substrate effects from the trench bottom and sidewalls influence
the developing microstructure depending on the interface energy with the
barrier or adhesion layer, the feature width and depth, and the thermally
induced stress conditions in subsequent processing. Electron backscatter
diffraction has been used in a number of investigations of thin Cu films and
lines to determine grain size and crystallographic texture. This work
summarizes some of the information gleaned using EBSD about structural
evolution in Cu films and lines. Also, the texture and grain size in single
level Cu lines as a function of line width is presented and analyzed in the
context of stress- state in the lines, and its effect on texture
development.
63.
Field, D. P., M. Kumar, et al. (2005). "Analysis of local orientation
gradients in deformed single crystals." Ultramicroscopy 103(1):
33-39.
Grain fragmentation and local orientation gradients in deformed single
crystals are characterized using electron backscatter diffraction (EBSD) to
obtain statistically reliable information. Interrogation of the dislocation
substructure is accomplished by extracting information gleaned from small
point-to-point misorientations as measured by EBSD Along with an estimate of
the geometrically necessary dislocation (GND) content, the point-to-point
deviation from an average grain orientation is described by an orientation
difference vector defined in Rodrigues space. Mapping of parameters such as
GND, and divergence and gradient fields created from analysis of the
difference vectors provide an alternative approach to obtain quantitative
information and images from EBSD data. Copyright 2004 Elsevier B.V. All
rights reserved.
64.
Field, D. P., M. M. Nowell, et al. (2004). Local orientation gradient and
recrystallization of deformed copper. 2nd International Conference on
Texture and Anisotropy of Polycrystals (ITAP 2), Metz, France, Balaban
Publishers; Scitec Publications, Switzerland.
The texture and grain boundary structure of recrystallized materials is
dependent upon the character of the deformed matrix, and the selective
nucleation and growth of crystallites from the deformation structure. Proper
description of the deformed matrix includes not only local crystallite
lattice orientation, but also dislocation content and gradients in
structural features that contribute to the heterogeneity of the nucleation
and growth processes. In-situ recrystallization experiments were performed
on pure copper deformed by equal channel angular extrusion, and
characterization of the structure on the surface of bulk specimens was
accomplished using the EBSD technique. The character of the structure where
nucleation preferentially occurs is presumed to be in heavily deformed
regions as nuclei were first observed in such microstructures. Grain growth
is observed to be heavily dependent upon twinning processes.
65.
Field, D. P., O. V. Kononenko, et al. (1997). "Relationship Between
Structure and Electromigration Characteristics of Pure Aluminum Films."
Materials Research Society Symposium Proceedings: 473.
66.
Field, D. P., O. V. Kononenko, et al. (2002). "The Microstructure of Cu
Films Deposited by the Self-Ion Assisted Technique." Journal of
Electronic Materials 31(1): 40-44.
The microstructures of Cu films deposited by the self-ion assisted,
partially ionized beam (PIB) deposition technique under two different
accelerating potentials, 0 KeV and 6 KeV, are compared. The 6 KeV film shows
a bimodal (111) fiber and (100) fiber texture with an abundance of twin
boundaries and a relatively large average grain size with a typical
lognormal distribution. The 0 KeV film consists of small, mostly (111)
oriented grains with islands of abnormally large (100) grains. The
controlling factors for the abnormal growth of the (100) grains are
discussed in relation to the observed microstructures, showing that all
factors necessary for abnormal (100) growth are present in the
films.
67.
Field, D. P., O. V. Kononenko, et al. (2003). Observation of grain growth in
Cu films by in-situ EBSD analysis. Materials, Technology and Reliability for
Advanced Interconnects and Low-k Dielectrics - 2003, San Francisco, CA,
United States, Mater. Res. Soc.
The microstructure of interconnect material is know to influence its
electromigration and stress-voiding properties. In addition to many factors
responsible for the microstructure development, the barrier layer could be a
major contributing factor as it forms the substrate for the copper films
above. The microstructure of the barrier films based on its deposition
technique could determine the final microstructure of the copper film. In
the present work we examine the effect of two different barrier layers (Ta
and TaN) and different stackings of these two materials on the
microstructure on the copper seed (PVD) and electroplated films using EBSD,
AFM and XRD. The results show that the plated films have a predominantly
(111) texture and uniform grain size. But the (111) texture maximum varied
with the barrier layer stacking underneath the plated film.
68.
Field, D. P., Q.-T. Jiang, et al. (2002). "Foreword." Journal of
Electronic Materials 31(1): 1.
This special issue contains papers presented at the International Workshop
on EBSD Applications to Electronic Materials, held at Washington State
University. Pullman, WA on May 17-18, 2001.
69.
Field, D. P., R. C. Eames, et al. (2006). "The role of shear stress in
the formation of annealing twin boundaries in copper." Scripta
Materialia 54(6): 983-986.
Annealing twin boundaries are important in the evolution of grain boundary
engineered materials. The development of annealing twins in face-centered
cubic metals is a function of stacking fault energy and a number of other
factors. It is observed that annealing heavily deformed copper under shear
stress tends to promote the formation of twin boundaries.
70.
Field, D. P., S. I. Wright, et al. (1996). Multi-Phase Texture Analysis by
Orientation Imaging Microscopy. Eleventh International Conference on
Textures of Materials (ICOTOM-11), Xi'an, China, international Academic:
Beijing.
71.
Field, D. P., S. I. Wright, et al. (2003). Microtextual analysis of Grain
Fragmentation in Aluminum. Thermec' 2003, Leganés, Madrid, Spain,
Trans Tech Publications Ltd.
Several recent investigations on the evolution of local orientation
gradients in individual grains during mechanical deformation have been
published. Some authors have observed that the character of the local
evolution gradients is correlated with the parent texture component. Most of
these studies of substructure evolution within deformed grains have been
performed in the transmission electron microscope (TEM) and are thus
restricted in their statistical scope. Using electron backscatter
diffraction (EBSD) in the SEM, it is possible to statistically characterize
this phenomena. This presentation reports on studies of grain fragmentation
and local orientation gradients using EBSD observations in high purity
aluminum.
72.
Field, D. P., T. Muppidi, et al. (2003). "Electron Backscatter
Diffraction Characterization of Inlaid Cu Lines for Interconnect
Applications." Scanning 25(6): 309-315.
Automated electron backscatter diffraction (EBSD) techniques have been used
to characterize the microstructures of thin films for the past decade or so.
The recent change in strategy from an aluminum-based interconnect structure
in integrated circuits to one based on copper has necessitated the
development of new fabrication procedures. Along with new processes,
complete characterization of the microstructures is imperative for improving
manufacturability of the Cu interconnect lines and in-service reliability.
Electron backscatter diffraction has been adopted as an important
characterization tool in this effort. Cu microstructures vary dramatically
as a function of processing conditions, including electroplating bath
chemistry, sublayer material, stacking sequence of sublayers, annealing
conditions, and line widths and depths. Crystallographic textures and grain
size and grain boundary character distributions, all of which may influence
manufacturability and reliability of interconnect lines, are ideally
characterized using EBSD The present discussion presents some results
showing structural dependence upon processing parameters. In addition, the
authors identify an in-plane orientation preference in inlaid Cu lines {111}
normal to the line surface and <110> aligned with the line direction.
This relationship tends to strengthen as the line width decreases.
73.
Field, D. P., T. W. Nelson, et al. (2001). "Heterogeneity of
Crystallographic Texture in Friction Stir Welds of Aluminum."
Metallurgical and Materials Transactions 32A(11): 2869-77.
Over the past decade, friction stir welding (FSW) has rapidly become an
important industrial joining process, particularly in the aluminum industry.
Included among the advantages of FSW are such important attributes as
improved weld strength and the elimination of cracking and porosity. During
the friction stir process, the metal undergoes a tortuous deformation path
that is not yet fully understood. The crystallographic texture that evolves
during FSW contains sharp spatial gradients that undoubtedly influence the
integrity of the weld and surrounding region in subsequent performance. The
locally measured textures are discussed in the context of the material flow
required to produce such textures, ultimately resulting in an estimate of
the flow field present during FSW.
74.
Field, D., J. John E. Sanchez, et al. (1997). "Analysis of
grain-boundary structure in Al-Cu interconnects." Journal of Applied
Physics 82(5): 2383-2392.
75.
Field, M. B., T. A. Byrne, et al. (1999). "The use of cubic Nd-Ba-Cu-O
seeds to create theta[100], 90 degrees-theta[100], and theta[001] tilt
Y-Ba-Cu-O grain boundaries." IEEE Transactions On Applied
Superconductivity 9(2): 1618-1621.
Using seeding techniques to control the orientation of grains, we have been
able to create a nide variety of
YBa2Cu3O6+x grain boundaries. In addition
to five domain samples with 90 degrees[100] twist and tilt grain boundaries,
we have now developed a method to produce grain boundaries in the same
sample that have the misorientations theta[001] tilt, theta[100] tilt, and
90 degrees-theta[100], where the misorientation angle theta is fully
controllable. We will demonstrate how these boundaries can be synthesized,
give experimental evidence via polarized light microscopy and electron
backscatter patterns (EBSP) that the intended grain boundaries were indeed
formed, and discuss the importance of these boundaries in future grain
boundary studies.
76.
Field, R. D. and P. A. Papin (2004). "Location specific in situ TEM
straining specimens made using FIB." Ultramicroscopy 102(1):
23-26.
A method has been devised and demonstrated for producing in situ straining
specimens for the transmission electron microscope (TEM) from specific
locations in a sample using a dual-beam focused ion beam (FIB) instrument.
The specimen is removed from a polished surface in the FIB using normal
methods and then attached to a pre-fabricated substrate in the form of a
modified TEM tensile specimen. In this manner, specific features of the
microstructure of a polished optical mount can be selected for in situ
tensile straining. With the use of electron backscattered diffraction
(EBSD), this technique could be extended to select specific orientations of
the specimen as well.
77.
Field, R. D., K. T. Hartwig, et al. (2002). "Equal-Channel Angular
Extrusion of Beryllium." Metallurgical and Materials Transactions A
33(March): 965-972.
78.
Fijiwara, K. and Z. Horita (2001). "Structural Analysis of
Diffusion-Couple Interface using EBSP." Materia Japan 40(7):
634-637.
79.
Findeling-Dufour, C., A. Gicquel, et al. (1998). "Growth of Large
Single-Crystal Diamond Layers - Analysis of the Junctions Between Adjacent
Diamonds." Diamond and Related Materials 7: 986-998.
80.
Fionova, L. K. (1994). "Grain-Boundary Ensembles in Materials with fcc,
Bcc and Diamond Structures." Materials Chemistry and Physics
37(3): 201-224.
81.
Fischer, R., L. T. F. Eleno, et al. (2006). "Precipitation of Cr-rich
phases in a Ni–50Al–2Cr (at.%) alloy." Intermetallics
14(2): 156-162.
An as-cast Al-rich B2-ordered Ni–50Al–2Cr alloy was heat-treated
at 550 °C for 500 h and then analysed by using atom probe field-ion
microscopy (APFIM), scanning electron microscopy (SEM), energy-dispersive
X-ray analysis (EDX), electron backscatter diffraction (EBSD), and
transmission electron microscopy (TEM). Chromium-rich precipitates with
(unexpectedly) high Al contents were detected and identified as the
so-called ‘X-phase’. The α-chromium phase was also present
possessing a significantly lower Al content. Nanoscale B2-ordered NiAl
precipitates present in the X-phase as well as nanoscale X-phase
precipitates within B2-ordered NiAl were detected.
82.
Fleig, J., B. Rahmati, et al. (2005). "Oxidation of reduced
polycrystalline Nb-doped SrTiO3: Characterization of surface
islands." Surface Science 595(1-3): 115-126.
Structural and chemical phenomena observed after high temperature oxidation
(1200 degrees C for 30h) of initially reduced Nb-doped (5at.%)
polycrystalline SrTiO3 are reported. The reoxidation procedure
leads to the formation of Sr-rich islands on the surface. These islands
exhibit characteristic areal densities, shapes, and sizes that depend on the
surface orientation of the corresponding grain. A correlation between grain
orientation (determined by orientation imaging microscopy) and tendency
towards island formation was found and discussed in terms of surface
energies. The structure and the composition of the islands were investigated
by transmission electron microscopy and significant differences were
observed for islands of different height located on differently oriented
surfaces. While a small island stayed in the perovskite structure (despite a
gradual and partly strong Ti depletion) a crystal structure change was found
for a larger island containing Sr cations only.
83.
Fliervoet, T. F., M. R. Drury, et al. (1999). "Crystallographic
preferred orientations and misorientations in some olivine rocks deformed by
diffusion or dislocation creep." Tectonophysics 303(1-4):
1-27.
The development of crystallographic preferred orientations (CPO) and grain
misorientation distributions (MOD) in fine-grained (0.5–30 μm)
olivine rocks, experimentally deformed by diffusion creep and dislocation
creep has been investigated. The use of electron back-scattered diffraction
(EBSD), in a scanning electron microscope (SEM), has enabled the measurement
of CPO in rocks which are too fine-grained to be measured by conventional
U-stage methods. Our objective is to study the influence of deformation and
recrystallisation mechanisms on the CPO and MOD. The olivine rocks studied
were deformed in uni-axial compression, in a gas-medium apparatus, to
17–24% strain at temperatures of 1200–1300°C and 300 MPa
confining pressures. The samples show a trend of weaker CPO with lower flow
stress which may be related to an increasing component of grain boundary
sliding and diffusion creep. In the diffusion creep regime the CPO and MOD
are weak to random, whereas in the dislocation creep regime the CPO and MOD
are non-random but the MOD is principally controlled by the CPO. These
results confirm the idea, based on studies from metals, that the CPO and MOD
in olivine are characteristic of the deformation mechanism. Dynamic
recrystallisation during dislocation creep results in the occurrence of more
intermediate-angle (10–40°) grain boundaries than expected from
the CPO. In local areas of complete recrystallisation the MOD is controlled
by the CPO which implies that the statistical MOD retains no signature of
the initial recrystallisation process. In the dislocation creep regime small
grains have a weaker CPO compared to large grains. This result is consistent
with predictions from deformation mechanism maps which indicate that the
fine recrystallised grains deform by a combination of dislocation creep and
grain boundary sliding. The grain boundaries found in the deformed olivine
polycrystals are predominately high-angle boundaries with misorientations
between 60 and 117°. No obvious evidence has been found for the
occurrence of preferred misorientation, or special, grain boundaries.
84.
Fliervoet, T. F., S. White, et al. (1997). "Evidence for dominant
grain-boundary sliding deformation in greenschist- and amphibolite-grade
polymineralic ultramylonites from the Redbank Deformed Zone, Central
Australia." Journal of Structural Geology 19(12):
1495-1520.
85.
Flouriot, S., S. Forest, et al. (2003). "Strain localization at the
crack tip in single crystal CT specimens under monotonous loading: 3D Finite
Element analyses and application to nickel-base superalloys."
International Journal of Fracture 124(1-2): 43-77.
Three-dimensional Finite Element simulations of mode I crack tip fields in
Compact Tension specimens are presented for elastic ideally-plastic F.C.C.
single crystals. The computations are carried out within the framework of
classical continuum crystal plasticity for three crack orientations:
(001)Ý110¨, (110)Ý001¨ and (001)Ý100¨. The
attention is drawn on the strong differences between the plastic strain
field obtained at the free surface and in the mid-section of the specimens.
The results are compared, on the one hand, to analytical solutions for
stationary cracks in single crystals under plane strain conditions and, on
the other hand, to experimental tests on a single crystal nickel-based
superalloy at room temperature. For this material, both octahedral and cube
slip must be taken into account. A good agreement between experimental
observations and numerical results is found in the structure of the strain
localization bands observed at the free surface of (110)Ý001¨
cracked specimens. In particular, the evidence of kink banding near the
crack tip is provided, confirmed by EBSD orientation mapping. The measured
values of local lattice rotation are in agreement with the Finite Element
prediction.
86.
Fonda, R. W. and J. Bingert (2004). "Microstructural Evolution in the
Heat-Affected Zone of a Friction Stir Weld." Metallurgical and
Materials Transactions A 35A(5): 1487-1499.
The microstructure and crystallographic texture spanning the soft region of
the thermomechanically affected zone/heat-affected zone (TMAZ/HAZ) boundary
of a friction stir weld in 2519 Al were systematically investigated to
determine their contributions to the properties of that region. The
microstructure was shown to be the primary cause of softening at the
TMAZ/HAZ boundary. During welding, fine 0' precipitates responsible for much
of the strength in this alloy coarsen and transform to the equilibrium 0
phase in the HAZ and into the TMAZ, accounting for the observed softening
through the HAZ region. The higher temperatures achieved in the TMAZ
partially resolutionize the precipitates and allow the subsequent formation
of Guinier-Preston (GP) zones during cooling. These two processes are
responsible for the variation in microhardness observed in the TMAZ/HAZ
region. Texture analyses revealed significant differences in the
crystallographic texture across this region that were primarily due to
macroscopic rigid-body rotations of the grains, but do not account for the
observed softening. The effect of the observed microstructural evolutions on
the friction stir welding (FSW) deformation field and on the fracture
behavior of the weld are also discussed.
87.
Fortier, P., W. A. Miller, et al. (1997). "Triple Junction and
Grain-Boundary Character Distributions in Metallic Materials." Acta
Materialia 45(8): 3459-3467.
Triple junction and grain boundary orientations were obtained by electron
backscattered diffraction in high purity aluminium and copper, and in
copper-bismuth alloys, and were then characterized using the CSL, CAD and
I-line (O-lattice) geometrical models. A computer simulation was also
performed and compared to the experimental results. Relationships were
established between triple junction and grain boundary character
distributions using both experimental and computer simulated results. A
general trend was observed which shows an increase in special triple
junction character density with increasing special grain boundary character
content. An increased frequency of low angle and twin boundaries is shown to
lead to an increase in the I-line triple junction density.
88.
Forwood, C. T. and L. M. Clarebrough (1988). "Rigid Body Displacement
at a Faceted Epsilon-3 Boundary in Alpha-Iron." Physica Status Solidi A
105(2): 365-375.
89.
Fréchard, S., F. Martin, et al. (2006). "AFM and EBSD combined
studies of plastic deformation in a duplex stainless steel." Materials
Science and Engineering A 418(1-2): 312-319.
In situ tensile tests have been carried out with an atomic force microscope
(AFM) to observe plastic deformation of an austenitic–ferritic duplex
stainless steel (Uranus 50). The images show that, for austenite grains,
parallel equidistant steps corresponding to the emergence of slip planes
appear at the surface of the specimen for a low level of strain. For a high
level of strain, slip lines with different orientations are distributed
homogeneously within all the austenite grains whereas only a few signs of
plastic deformation are visible in ferrite grains. After deformation,
electron back scattered diffraction (EBSD) method has been used to determine
the crystallographic orientations of austenite and ferrite grains on the
areas observed by AFM. The combination of AFM and EBSD studies allows to
obtain a complete identification of activated slip systems observed on the
AFM images. It gives a deep insight on deformation processes in a duplex
stainless steel (Burgers vectors, number of dislocations per steps, ...).
The plastic deformation of ferrite grains is discussed in terms of slip
induced by the dislocation accumulation in the neighbouring austenite
grains.
90.
Francillette, H., B. Bacroix, et al. (1997). "Effect of initial
textures on deformation mechanisms and texture evolutions of Zrα
polycrystals deformed by channel-die compression tests." Materials
Science and Engineering A 234-236: 974-977.
91.
Francillette, H., B. Bacroix, et al. (1998). "Grain orientation effects
in Zr702 alpha polycrystalline samples deformed in channel die compression
at room temperature." Acta Materialia 46(12): 4131-4142.
Deformation mechanisms are determined in five zirconium polycrystalline
samples deformed by channel die compression at room temperature (T1-T5
textures). Slip systems are characterized by a slip trace analysis and
twinning systems by a misorientation calculation between twinned and
non-twinned parts of the grains, from Electron Back Scattering Diffraction
(EBSD) measurements. The analysis is completed by the measurement of
crystallographic texture evolutions and the examination of the stress-strain
curves. Prismatic glide and {10 (1) over bar 2} twinning are identified as
primary deformation modes and first-order pyramidal slip {10 (1) over bar 1}
and basal slip as secondary slip modes. The experimental study is completed
by a numerical approach using polycrystalline models which is consistent
with the experimental observations.
92.
Frank, F. C. (1988). "Orientation Mapping." Metallurgical
Transactions A 19(3): 403-408.
93.
Frei, H. and G. Grathwohl (1989). "Development of a
Piezotranslator-Based Bending Device for Insitu SEM Investigations of
High-Performance Ceramics." Journal of Physics E 22(8):
589-593.
94.
Freitag, K., A. P. Boyle, et al. (2004). "The use of electron
backscatter diffraction and orientation contrast imaging as tools for
sulphide textural studies: example from the Greens Creek deposit
(Alaska)." Mineralium Deposita 39: 103-113.
The Greens Creek polymetallic massive sulphide deposit is hosted in a
typical polyphase deformed lower greenschist facies orogenic setting. The
structure of the host rocks is well constrained, exhibiting a series of
three superimposed ductile deformations followed by two brittle episodes.
The ore is found both in fold hinges where early-formed depositional
features are preserved and in fold limbs where primary features are
typically strongly modified or obliterated. Samples from both settings have
been investigated using electron backscatter diffraction (EBSD) coupled with
forescatter orientation contrast (OC) imaging in order to observe the
effects of deformation and lower greenschist facies metamorphism on pyrite.
Results suggest that colloform pyrite may preserve information relevant to
palaeoenvironment, that apparently simple textures are generally more
complex, and that pyrite can deform plastically by dislocation glide and
creep processes at lower temperatures and/or strain rates than generally
accepted. This analysis indicates that EBSD and OC imaging provide powerful
tools for observing textural relationships in pyrite that are not shown by
more traditional methods. They should become routine tools for pyrite
texture analysis.
95.
Frese, K., V. Trommsdor, et al. (2003). "Olivine [100] normal to
foliation: lattice preferred orientation in prograde garnet peridotite
formed at high H2O activity, Cima di Gagnone (Central Alps)."
Contributions to Mineralogy and Petrology 145: 75-86.
Automated electron backscattered diffraction (EBSD) was applied using a
scanning electron microscope to obtain lattice preferred orientation (LPO)
data for olivine in garnet peridotites of the Central Alps. As a reference
frame, the LPOs of enstatite were also investigated. In the garnet
peridotite at Cima di Gagnone (CDG), a weak foliation carrying a distinct
lineation is present. The lineation is characterized by elongated enstatite,
olivine and poikiloblastic garnet. Olivine shows a very unusual LPO with
[100] normal to foliation and [001] parallel to lineation.
Achsenverteilungsanalyse (AVA) maps demonstrate that [001] of olivine grains
corresponds quite well to their maximum length axes which are preferentially
parallel to the lineation. Numerous planar hydrous defects within (001)
planes of olivine are marked by palisades of ilmenite rods and show a
preferred orientation normal to lineation. Calculated P-wave velocities for
CDG are fastest (8.32 km s)1) normal to foliation with a relatively low
anisotropy (2.9%). Compared to mantle peridotites with the usual (010)[100]
LPO where the fastest Vp direction is towards the lineation, the
relationship between flow geometry and seismic anisotropy is significantly
different at CDG. Several mechanisms for the formation of the LPO type at
CDG are considered, with glide possible on (100)[001] of olivine. On the
basis of field data as well as petrographic and petrologic evidence, it has
been demonstrated that the CDG garnet peridotite formed by prograde
metamorphism from a hydrous protolith at pressures and temperatures of about
3.0 GPa and 750° C, respectively. The CDG LPO is interpreted to have
formed during hydrous subduction zone metamorphism. The same interpretation
may hold for the previously investigated olivine LPO at Alpe Arami, which is
similar to that at the nearby CDG. The observed anomalous LPO is no proof
for ultradeep (>3.0 GPa) conditions. Copyright Springer-Verlag
2003
96.
Friedel, F., D. Raabe, et al. (2003). "High-Resolution EBSD
Investigation of Deformed and Partially Recrystallized IF Steel."
Advanced Engineering Materials 5(8): 566-570.
The recrystallization of titanium-alloyed interstitial-free steel (IF steel)
has been investigated by high-resolution electron backscattered diffraction
(EBSD) measurements and transmission electron microscopy (TEM) observations.
The deformed microstructure of the cold rolled material can be subdivided
into three different groups. These three types of microstructure are
characterized by their orientations and internal local misorientations. The
development of these three regions during recrystallization annealing has
been observed. Nucleation from γ-fiber orientations but also from other
orientations was found. Comparison of EBSD and TEM results indicates some
limitations of high-resolution EBSD measurements concerning the observation
of subgrain structures
97.
Friedel, F., E. Zimmerman, et al. (1999). "Examples of Microstructure
Analysis by Orientation Imaging Microscopy." Steel Research
70(12): 524-529.
98.
Frolov, M. P., G. D. Hager, et al. (2004). Electric properties,
spectroscopy, and singlet delta oxygen yield of electron-beam sustained
discharge in oxygen gas mixtures. Gas and chemical lasers, and applications
III, San Jose, California, USA, SPIE-Int. Soc. Opt. Eng.
Electric properties and spectroscopy of an e-beam sustained discharge (EBSD)
in oxygen and oxygen gas mixtures at gas pressures up to 100 Torr was
experimentally studied in large excitation volume (approximately=18 liter).
The discharge in pure oxygen and its mixtures with noble gases was shown to
be very unstable and characterized by low input energy. When adding small
amount of carbon monoxide or hydrogen, the electric stability of the
discharge increases, specific input energy per molecular component being
higher more than order of magnitude and coming up to 6.5 kJ/(l atm).
Theoretical calculations demonstrated that for the experimental conditions
the singlet delta oxygen yield may reach approximately=20% exceeding its
threshold value needed for oxygen-iodine laser operation at room
temperature. The results of experiments on spectroscopy of the singlet delta
and singlet sigma oxygen states in the EBSD are presented.
99.
Frolov, M. P., G. D. Hager, et al. (2004). Electron-beam sustained discharge
in oxygen gas mixtures: singlet delta oxygen production for oxygen-iodine
laser. High Power Laser Ablation V, Taos, New Mexico, USA, SPIE-Int. Soc.
Opt. Eng.
Electric properties and spectroscopy of an e-beam sustained discharge (EBSD)
in oxygen and oxygen gas mixtures at gas pressure up to 100 Torr were
experimentally studied. The pulsed discharge in pure oxygen and its mixtures
with noble gases was shown to be very unstable and characterized by low
input energy. When adding small amount of carbon monoxide or hydrogen, the
electric stability of the discharge increases, specific input energy (SIE)
per molecular component being more than order of magnitude higher and coming
up to 6.5 kJ/(l atm) for gas mixture O2:Ar:CO = 1:1:0.1. The
results of experiments on spectroscopy of the singlet delta oxygen
O2(a1 Deltag)(SDO) and
O2(b1 Sigmag+) states in the
EBSD are presented. The calibration of the optical scheme for measuring the
SDO absolute concentration and yield using the detection of luminescence of
the SDO going from a chemical SDO generator was done. The preliminary
measurement of the SDO yield demonstrated that it was approximately=3% for
the SIE of approximately=1 kJ/(l atm), which is close to the results of
theoretical calculations for such a SIE. Theoretical calculations
demonstrated that for the SIE of 6.5 kJ/(l atm) the SDO yield may reach
approximately=20% exceeding its threshold value needed for oxygen-iodine
laser operation at room temperature, although a part of the energy loaded
into the EBSD goes into the vibrational energy of the molecular admixture,
(which was experimentally demonstrated by launching a CO laser operating on
an oxygen-rich mixture O2:Ar:CO = 1:1:0.1 and measuring its
small-signal gain).
100.
Frolov, M. P., G. D. Hager, et al. (2004). "Pulsed
electron-beam-sustained discharge in oxygen-containing gas mixtures:
Electrical characteristics, spectroscopy, and singlet oxygen yield."
Quantum Electronics 34(9): 865-870.
The electrical and spectroscopic characteristics of electron-beam-sustained
discharge (EBSD) in oxygen and oxygen-containing gas mixtures are studied
experimentally under gas pressures up to 100 Torr in a large excitation
volume (similar to 18 L). It is shown that the EBSD in pure oxygen and its
mixtures with inert gases is unstable and is characterised by a small
specific energy contribution. The addition of small amounts (similar to 1% -
10%) of carbon monoxide or hydrogen to oxygen or its mixtures with inert
gases considerably improves the stability of the discharge, while the
specific energy contribution W increases by more then an order of magnitude,
achieving similar to 6.5 kJ L-1atm-1 per molecular
component of the gas mixture. A part of the energy supplied to the EBSD is
spent to excite vibrational levels of molecular additives. This was
demonstrated experimentally by the initiation of a CO laser based on the
O2: Ar: CO = 1: 1: 0.1 mixture. Experimental results on
spectroscopy of the excited electronic states
O2(a1Dg) and
O2(b1Σg+), of oxygen
formed in the EBSD are presented. A technique was worked out for measuring
the concentration of singlet oxygen in the
O2(a1δg) state in the afterglow of
the pulsed EBSD by comparing with the radiation intensity of singlet oxygen
of a given concentration produced in a chemical generator. Preliminary
measurements of the singlet-oxygen yield in the EBSD show that its value
similar to 3 % for W similar to 1.0 kJ L-1atm-1 is in
agreement with the theoretical estimate. Theoretical calculations performed
for W similar to 6.5 kJ L-1atm-1 at a fixed
temperature show that the singlet-oxygen yield may be similar to 20 %, which
is higher than the value required to achieve the lasing threshold in an
oxygen-iodine laser at room temperature.
101.
Fuji, A., K. Ikeuchi, et al. (2004). "Interlayer growth at interfaces
of Ti/Al-1%Mn, Ti/Al4.6%Mg and Ti/pure Al friction weld joints by post-weld
heat treatment." Science and Technology of Welding and Joining
9(6): 507-512.
The interlayer growth at interfaces of Ti/Al%Mn and Ti/Al-4.6%Mg weld joints
was studied by postweld heat treatment. The heating temperatures ranged from
676 to 873 K (400-600DGC) and maximum heating time was 360 ks (100 h). The
basic mechanism of interlayer growth for pure Tilpure Al friction weld joint
was also estimated. The interlayer growth rate of Ti/Al-4.6%Mg joint was
much faster than for the Ti/Al-1%Mn joint. The interlayer mainly consisted
of (Al,Si)3Ti for the Ti/Al-1%Mn joint, and Al18Mg3Ti2 for the Ti/Al-4.6%Mg
joint. While the interlayer grew from Al alloy substrate to the Ti side, for
the Ti/Al1%Mn joint, it grew from the Ti substrate to the Al alloy side for
the Ti/A1-4.6%Mg joint. The interlayer growth stopped for several hours on
heating, for 36 ks (10 h). Neither linear nor parabolic time-dependence
relations could be exactly fit to the interlayer growth rate for both
joints. The interlayer growth of Ti/AI1%Mn was proportional to heating time
raised to approximately 0.85. The crystal direction of Al3Ti interlayer
growth of the Ti/Al joint was close to < 001 and < 111 > directions
obtained by OIM method. Nucleation and nuclei growth were observed at the
interface of the Ti/Al joint. The nucleation and the nuclei growth are the
reason for the phenomena (tirne dependence) described above.
102.
Fujii, S., S. Shikata, et al. (2005). "Effect of crystalline quality of
diamond film to the propagation loss of surface acoustic wave devices."
IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
52(10): 1817-1822.
Diamond films with various crystal qualities were grown by chemical vapor
deposition on silicon wafers. Their crystallinity was characterized by Raman
scattering and electron backscattering diffraction. By fabricating a device
structure for surface acoustic wave (SAW) using these diamond films, the
propagation loss was measured at 1.8 GHz arid compared with the
crystallinity. It was found that the propagation loss was lowered in
relatively degraded films having small crystallites, a narrow distribution
in the diamond crystallite size, and preferential grain orientation. This
experiment clarifies diamond film characteristics required for
high-frequency applications in SAW filters.
103.
Fujii, S., Y. Takada, et al. (2005). Low phase noise VCSO with diamond SAW
resonators. 2005 IEEE International Frequency Control Symposium and
Exhibition, Vancouver, British Columbia, Canada.
L and S-band VCSOs with diamond SAW resonators have been developed based on
Lesson's model. First, the crystallinity of diamond thin film required for
high-frequency SAW resonators was characterized by Raman scattering and
electron backscattering diffraction. From these measurements, it was found
that the propagation loss of SAW was lowered in relatively degraded films
having small crystallites, and preferential grain orientation. After
optimizing CVD growth conditions, a 3.4 GHz diamond SAW resonator with low
insertion loss and high Q-value has been successfully developed. Second, by
using the diamond SAW resonators, and employing low temperature co-fired
ceramics, L and S-band VCSOs with a low phase noise were successfully
obtained.
104.
Fujioka, H., S. noue, et al. (2006). "Epitaxial growth of AlN on Cu(1 1
1) substrates using pulsed laser depositio." Journal of Crystal Growth
289(2): 574-577.
We have succeeded in the epitaxial growth of AlN on Cu(1 1 1) substrates
using pulsed laser deposition (PLD) for the first time. We achieved
atomically flat surfaces of Cu(1 1 1) by annealing in an ultra high vacuum
chamber. In situ X-ray photoelectron spectroscopy and reflection high-energy
electron diffraction studies revealed that the native oxide layers on the
surfaces had been successfully removed and that the Cu surfaces were
reformed by the segregation of antimony atoms, incorporated in the
substrates as impurities. We found that AlN (0 0 0 1) grows epitaxially on
Cu(1 1 1) at a substrate temperature of as low as 500° C with in-plane
epitaxial relationships of AlN 1120 //Cu 110. Electron backscattering
diffraction measurements showed that neither 30° rotational domains nor
cubic phase domains exist in the AlN films. Spectroscopic ellipsometry
measurements revealed that no interfacial layers exist at the AlN/Cu hetero
interfaces within the limits of detection. These results indicate that the
PLD low-temperature growth technique permits the preparation of high-quality
AlN expitaxial films on single-crystal metal substrates.
105.
Fujita, K., T. Hagisato, et al. (2006). "A crystallographic
homogenization elastic/crystal viscoplastic finite element analysis of pure
iron polycrystal material by employing the kinematic hardening rule."
Transactions of the Japan Society of Mechanical Engineers 72(1):
1-7.
In this study, multi scale analyses, by using the crystallographic
homogenization based semi-implicit finite element code, have been carried
out to indicate a plastic strain induced texture evolution and
macro-continuum yield loci evolution. This crystallographic homogenization
finite element code has employed the double scale hierarchical structure,
which consists of a polycrystal microstructure and a macro-continuum. We
focus to discuss "How to define a proper microstructure for the double
scale finite element analysis, by employing the real polycrystal
aggregation, which has been measured by SEM EBSD apparatus". For
scaling up from the polycrystal microstructure to the macro-continuum, we
looked at the periodicity of crystal orientation distribution, which is one
of morphological factors to feature the polycrystal structure itself, which
is named as "texture". Through a statistical stydy of these
measured polycrystal morphologies, finally we obtaine a realistic
polycrystal unit cell of the microstructure, which can be adopted for multi
scale finite element analyses. The availability of this code to predict the
plastic deformation induced anisotropy and kinematical hardening is
confirmed.
106.
Fujita, Y., K. Nishimoto, et al. (2005). Crystalline controlled cladding of
Ni-base single crystal superalloy by diode laser. 24th International
Congress on Applications of Lasers and Electro-Optics, ICALEO 2005, Miami,
Florida, USA.
Microstructure and crystallographic orientation in the surface-melted region
and clad region by diode laser have been investigated using Ni-base single
crystal superalloy CMSX-4. The laser power and scanning speed in laser
surface melting and cladding were varied. The microstructure and crystal
orientation were analyzed by optical microscopy, scanning electron
microscopy and electron backscattered diffraction pattern. The
surface-melted region under the low heat input condition was found to be
solidified as the single-crystalline state with uni-directional dendrites
which grew along the 001 directions. The surface-melted region under
intermediate heat input condition was also single-crystalline with dendrites
which grew along the 001, 010 and 100 directions. In contrast, the
surface-melted region under high heat input condition was consisted of
polycrystal with stray crystals. The theoretical analysis of growth
direction of dendrite and the constitutional supercooling at the
solidification front indicated that the stray crystal tended to be formed
with low scanning speed and high laser power. Microstructural observation
revealed that the cladding layer grew epitaxially on the base metal, and
that crystalline controlled cladding could be achieved by laser
cladding.
107.
Fujiwara, K., K. Nakajima, et al. (2005). "Liquid phase epitaxial
growth of Si layers on Si thin substrates from Si pure melts under
near-equilibrium conditions." Japanese Journal of Applied Physics Part
1 44(7A): 5092-5095.
The growth of Si epitaxial layers on Si substrates from Si pure melts was
attempted under near-equilibrium conditions by dipping-type liquid phase
epitaxial (LPE) growth, in order to eliminate the doping effect from metal
solutions on the purity of the Si epitaxial layers. Si epitaxial layers can
be grown on Si substrates from a Si pure melt only when the temperature of
the Si growth melt is kept 1-20.6L C above the melting point of
Si (1414ly reduce C) and the growth melt is cooled just after the substrate
is dipped in the growth melt. The Si substrate, Si epitaxial layers, and Si
polycrystals can be clearly distinguished in the electron back-scattering
diffraction pattern (EBSP) image of their cross sections. The growth rate of
Si LPE layers during cooling clearly increases as the amount of overheating
of the growth melt decreases from 2 to 1ively. Ov C and the cooling rate
increases from 0.4 to 1.0 mm/min.
108.
Fukuda, Y., K. Oh-ishi, et al. (2004). "The application of
equal-channel angular pressing to an aluminum single crystal." Acta
Materialia 52: 1387-1395.
An investigation was conducted to examine the nature of the deformed
microstructure when an aluminum single crystal of known orientation is
subjected to equal-channel angular pressing (ECAP). The experiment was
performed using a single crystal that was initially oriented within the
entrance channel of the die so that the (1 1 1) slip plane was parallel to
the theoretical shear plane and the [1 1 0] slip direction lay parallel to
the direction of shear. The crystal was subjected to a single pass at room
temperature and then examined using various microscopic techniques including
orientation imaging microscopy and transmission electron microscopy. It is
shown that the detailed experimental observations are fully consistent with
the expectations from crystallographic considerations except only in the
vicinity of the lower die wall where frictional effects are present.
109.
Fukuoka, C., K. Morishima, et al. (2002). "Misorientation development
in grains of tensile strained and crept 2.25%Cr–1%Mo steel."
Scripta Materialia 46: 61-66.
Misorientation within grains of 2.25%Cr–1%Mo steel developed by
tensile and creep testing has been measured by electron back scattered
patterns. It has been shown that the misorientation within grains linearly
increases with increase of plastic strains of the samples. This relationship
has also been derived from a simplified model.
110.
Fukutomi, H., M. Hasegawa, et al. (2002). Orientation Distribution in
Dynamically Recrystallized Nickel. ICOTOM 13, Seoul, Korea, Trans Tech
Publications Inc.
Changes in the orientation distribution during dynamic recrystallization are
investigated by texture measurements and EBSP analyses. Uniaxial compression
tests are conducted in vacuum on polycrystalline pure nickel in temperatures
and strain rates ranging from 873K to 1573K and 1.0x10-4s to
1.0x10-2s-1, respectively. It is found that weak
texture develops under the deformations at lower temperature and higher
strain rate conditions, namely the conditions where the Zener-Hollomon
parameter Z is high (hereafter called as high Z conditions), while almost no
texture is observed at higher temperature and lower strain rate conditions
(hereafter called as low Z conditions). The behavior of texture formation at
low Z conditions is different from the dynamic recrystallization of
intermetallic compound TiAl investigated before. EBSP measurements show that
new grains having random orientations are formed in the regions close to
grain boundaries at high Z conditions. It is suggested that the serration of
grain boundaries plays an important role to produce the area having random
orientations in the neighborhood of grain boundaries. The orientation of
these grains change towards the stable orientation for uniaxial compression,
resulting in the formation of weak texture. At the deformation in low Z
conditions new grains are formed by the migration of the existing grain
boundaries. It is found that many twins are formed during the migration. At
the deformation under the lowest Z condition, almost half of the high angle
grain boundaries are twin boundaries. It is concluded that the texture
formation in dynamic recrystallization is dominated by the local deformation
affected by the shape change of grai boundary and twin formation during the
migration of existing grain boundaries.
111.
Fundenberger, J. J. M., A.; Bouzy, E.; Lecomte, J. S. (2003). "System
for creating orientation maps using TEM." Materials Chemistry and
Physics 81(2-3): 535-537.
Electron back-scattered diffraction (EBSD) in scanning electron microscopy
(SEM) is already extensively used for creating orientation-based
microstructure images of polycrystalline materials. In an analogous way,
Kikuchi patterns have been recently applied for creating polycrystalline
orientation maps using a transmission electron microscope. Main components
of the new system are similar to those of the SEM-based systems. The first
steps are pattern acquisition and correction of the images. They are
subsequently followed by automatic indexing of the patterns. Finally, from
orientations obtained in a grid of points, a map is created. The system
using transmission electron microscopy (TEM) has a good spatial resolution
of about 10 nm. Its accuracy in orientation determination (approximately=0.1
degrees) is better than the accuracy of EBSD systems.
112.
Fundenberger, J. J., A. Morawiec, et al. (2004). Advances in automatic TEM
based orientation mapping. 2nd International Conference on Texture and
Anisotropy of Polycrystals (ITAP 2), Metz, France, Balaban Publishers;
Scitec Publications, Switzerland.
The paper is an account of TEM based automatic orientation mapping
summarizing more than two years of using the system. Following a brief
introduction of the system elements, some representative applications are
described. We focus on the characterization of fine-grain materials, mapping
of low symmetry materials (metastable chromium carbide) and semi-automatic
analysis of misorientations in a fully lamellar polycrystalline (γ +
α2) TiAl alloy. Moreover, the current state of the TEM
based system is discussed and compared to EBSD systems. In particular, the
issues of spatial resolution, accuracy, map acquisition time, reliability
are considered.
113.
Fundenberger, J.-J., A. Morawiec, et al. (2003). "Polycrystal
orientation maps from TEM." Ultramicroscopy 96(2):
127-137.
Determination of topography of crystallite orientations is an important
technique of investigation of polycrystalline materials. A system for
creating orientation maps using transmission electron microscope (TEM)
Kikuchi patterns and Convergent beam electron diffraction patterns is
presented. The orientation maps are obtained using a step-by-step beam scan
on a computer-controlled TEM equipped with a CCD camera. At each step,
acquired diffraction patterns are indexed and orientations are determined.
Although, the approach used is similar to that applied in SEM/electron back
scattered diffraction (EBSD) orientation imaging setups, the TEM-based
system considerably differs from its SEM counterpart. The main differences
appear due to specific features of TEM and SEM diffraction patterns. Also,
the resulting maps are not equivalent. On these generated by TEM, the
accuracy of orientation determination can be better than 0.1 deg. The
spatial resolution is estimated to be about 10nm. The latter feature makes
the TEM orientation mapping system an important tool for studies at fine
scale unreachable by SEM/EBSD systems. The automatic orientation mapping is
expected to be a useful complement of the conventional TEM contrast images.
The new technique will be essential for characterization of fine structure
materials. To illustrate that, example maps of an aluminum sample produced
by severe plastic deformation are included.
114.
Furu, T., O. Lohne, et al. (1994). Electron Back Scattering Pattern (EBSP):
A powerful tool in studying recrystallization of metals. Fifty-Second Annual
Meeting Microscopy Society of America/Twenty-Ninth Annual Meeting Microbeam
Analysis Society, New Orleans, LA, San Francisco Press, Inc.
The Electron Back Scattering Pattern Technique (EBSP) for measurements of
crystal orientations is now a well established technique for microstructure
determination. The application of the technique to material problems has
increased quite substantially the last years. When studying
recrystallization process in detail a relatively large area of a specimen
has to be investigated to obtain good statistical results. The EBSP
technique was used to follow the local texture evolution during
transformation and at the same time able to analyze changes in the
untransformed matrix. [References: 5]
115.
Furu, T., R. Orsund, et al. (1995). "Subgrain Growth in Heavily
Deformed Aluminum-Experimental Investigation and Modeling Treatment."
Acta Metallurgica et Materialia 43(6): 2209-2232.
116.
Furuhara, T., G. Miyamoto, et al. (2005). Nucleation on Irrational
Interphase Boundaries in Diffusional Phase Transformations of Steels. Solid
to Solid Phase Transformations in Inorganic Materials 2005, Phoenix,
Arizona, USA, TMS.
Heterogeneous nucleation of ferrite on inclusions/precipitates dispersed in
austenite is important in refining microstructures of low and medium carbon
steels. In the present study, characteristics of intragranular ferrite
nucleated on the B1-type complex inclusions/precipitates in austenite are
discusssed. The intraganular ferrite transformation is promoted remarkably
with the presence of V(C,N) formed on the incoherent MnS inclusion. Those
V(C,N) precipitates exhibit irrational and non-specific orientation
relationships with respect to the austenite. Intragranular ferrite is
idiomorphic for small undecooling but becomes acicular as the transformation
temperature is lowered. The idiomorphic ferrites tend to hold low-energy
orientation relationships with respect to V(C,N), resulting in irrational
and non-specific orientation relationships between the ferrite and
austenite. For the acicular ferrite, near Kurdjumov-Sachs orientation
relationships are achieved with respect to the austenite. V(C,N)
precipitation at austenite grain boundaries leads to an increase in the
irrationality of the orientation relationship between grain boundary ferrite
and the austenite matrix.
117.
Furuhara, T., Y. Toji, et al. (2003). Dynamic Recovery and Recrystallization
in Beta-Titanium Alloys. Thermec' 2003, Leganés, Madrid, Spain, Trans
Tech Publications Ltd.
Microstructure change during hot deformation was studied in ß titanium
alloys, Ti-10V-2Fe-3Al and Ti-15V-3Cr-3Sn-3Al. After ß solution
treatments, isothermal compression was performed at various temperatures in
the ß single phase and in the (α + ß) two-phase region at
initial strain rates between 4.2 x 10-1 ~ 4.2 x 10-5
s-1. When the specimens are deformed in the ß single phase
region, a recovered structure was formed within ß grains although
discontinuous dynamic recrystallization occures in the vicinity of ß
grain boundary. When deformation was performed in the (α + ß)
two-phase region just below the ß transus, discontinuos
recrystallization around ß grain boundary is suppressed due to the
pinning effect by grain boundary α precipitate, resulting in a mostly
recovered structure. Contrarily, when the specimen is deformed at the
temperature where a large amount of a precipitates, dynamic continuous
recrystallization uniformily in ß matrix resulting in the formation of
(α + ß) microduplex structures containing high angle ß
boundaries. The size of recrystallized ß grains decreases as strain
rate increases or deformed temperature is lowered in a good correalation
with Zener-Holloman parameter.
118.
Furukawa, M., N. Gao, et al. (2004). "Microstructural evolution in a
spray-cast aluminium alloy during ECA pressing and in subsequent heat
treatment." JOM 56(11): 217.
The microstructures of a spray-cast Al-7034 (Al-Zn-Mg-Cu) alloy after
processing through equal-channel angular pressing (ECAP) were studied using
electron back-scatter diffraction (EBSD) and differential scanning
calorimetry (DSC). The ageing response and recrystallisation softening post
ECAP were studied by hardness testing and DSC. The results demonstrate there
is a relatively rapid increase in the fraction of high-angle boundaries
during the initial ECAP passes and a subsequent more gradual increase in
further passes. The crystallographic textures introduced by ECAP are
analysed. For the Al-7034 alloy, the DSC analysis identifies the occurrence
of several thermal effects during heating involving the formation,
coarsening, dissolution and melting of the eta phase.
119.
Furuno, K., H. Akamatsu, et al. (2004). "Microstructural development in
equal-channel angular pressing
using a 60° die." Acta Materialia 52: 2497-2507.
Billets of pure aluminum and an Al–1%Mg–0.2%Sc alloy were
successfully processed using equal-channel angular pressing (ECAP) with a
die having an internal channel angle of 60°. Careful inspection of the
microstructures after ECAP revealed excellent agreement, at both the
macroscopic and the microscopic levels, with the theoretical predictions for
shearing using a 60° die. The grain sizes introduced with the 60°
die were slightly smaller than with a conventional 90° die; thus, the
values with these two dies were ~1.1 and ~1.2 µm in pure Al and ~0.30
and ~0.36 µm in the Al–Mg–Sc alloy, respectively. Tensile
testing of the pure aluminum at room temperature revealed similar
strengthening after processing using either a 60° or a 90° die. In
tests conducted at 673 K, the Al–Mg–Sc alloy processed with the
60° die exhibited significantly higher elongations to failure due
primarily to the larger strain imposed with this die. It is shown using
orientation imaging microscopy that superplastic flow in the
Al–Mg–Sc alloy produces an essentially random texture and a
distribution of boundary misorientations that approximates to the
theoretical distribution for an array of randomly oriented grains.
120.
Furuta, T., J. Hwang, et al. (2005). "EBSP analysis on microstructure
of gum metal after plastic deformation." Journal of the Japan Institute
of Metals 69(11): 953-961.
EBSP (electron backscattering pattern) analysis was performed on
microstructure of three β titanium alloy specimens after cold working
to study peculiar plastic behavior of the multifunctional alloy, Gum Metal.
The specimens employed were Ti-36% Nb-2%Ta-3%Zr-0.3%O (mass%) alloy (Gum
Metal) and two reference alloys having lower and higher bcc phase stability
than that of Gum Metal. Deformation twinning of [332] <113> was
observed in the specimen with lower bcc stability, and dislocation glide in
the specimen with higher bcc stability. Orientation boundaries with rotation
angle of 10-30 degrees were observed in Gum Metal specimen, and they are
considered to be identical to the giant planar faults which were observed in
TEM in the previous study. It seems that the giant faults act as grain
boundaries and numerous subgrains are generated in the later stage of
plastic deformation. Amount of crystallographic rotation in deformed Gum
Metal specimens was very large, which implies that huge elastic energy was
stored during plastic deformation.
121.
Furuta, T., J. Hwang, et al. (2005). "Elastic deformation behavior of
multi-functional Ti-Nb-Ta-Zr-O alloys." Materials Transactions
46(12): 3001-3007.
We investigated the effect of cold working on the elastic properties of a
newly developed multi-functional β titanium alloy, GUM METAL, using
in-situ XRD and EBSP analysis. Mechanical and physical properties are
changed dramatically by cold working. The alloy has a low elastic modulus
(40 GPa), high strength (more than 1100 MPa), high elastic deformability
(2.5%) and super-plastic like deformability at room temperature without work
hardening. The elastic behavior of the cold worked specimen shows
non-linearity, with the gradient of the stress--strain curve in the elastic
region continuously decreasing with a stress increase. In-situ XRD
measurements during tensile loading show that all β peaks shift
monotonically to higher 2θ angles with increasing tensile strain up to
2.7%. This result suggests that the elastic behavior in the alloy is not
accompanied by phase transformations, such as stress-induced α''.
Additionally, EBSP analysis reveals that the deformation mode in the alloy
does not relate to {112} <111> or {332} <113> twinning. The
microstructure of the alloy during deformation is characterized by localized
distorted regions ranging in size from several tens of micrometers to
submicrometers, with elastic strain located hierarchically in the alloy. It
is likely that this microstructure is attributable to its elastic anomaly,
which arises at this specific alloy composition of the multifunctional
alloy. The above elastic anomaly in the alloy seems to contribute to the
development of the unique microstructure during plastic deformation, as well
as to its macroscopic elastic behavior.
122.
Futamura, Y., M. Natori, et al. (2004). Difference in Recrystallization
Behavior between Martensite and Deformed Ferrite. Second Joint International
Conference on Recrystallization and Grain Growth, ReX & GG2, SF2M,
Annecy, France, Trans Tech Publications Ltd.
Microstructural change and softening behavior during annealing were
invesigated for deformed ferrite and lath martensite in an ultralow carbon
1.5mass%Mn-0.0018mass%B steel, and then the difference in recrystallization
behavior between the materials was discussed in terms of the nucleation site
of recrystallized grains. The ferritic and martensitic materials were
obtained by furnace-cooling and water-quenching, respectively, after
solution treatment. The ferritic material was cold-rolled at a reduction of
80% to give the same dislocation density as of the martensitic material. The
deformed ferritic material contains a large number of geometrically
necessary (GN) boundaries with large misorientations, while the martensitic
material only contains original grain boundaries such as prior austenite
grain boundaries, packet boundaries and block boundaries. The
recrystallization during annealing is markedly retarded in the martensitic
material compared with the deformed ferritic material. As a result, the time
for completing the recrystallization was roughly a hundred times longer in
the martensitic material than in the deformed ferritic material. This is due
to the difference in nucleation site of recrystallized grains, that is the
GN boundaries introduced by the deformation for the ferritic material, and
only the original grain boundaries for the martensitic material.
123.
Futamura, Y., T. Ando, et al. (2005). Crystallography of Ferrite-Austenite
Phase Transformation Induced by Nitrogen Absorption in Fe-25Cr Alloy. Solid
to Solid Phase Transformations in Inorganic Materials 2005, Phoenix,
Arizona, USA, TMS.
The phase transformation from ferrite to austenite induced by solution
nitriding was discussed in 25mass%Cr ferritic stainless steel on the basis
of crystallographic analysis by EBSP method. In the early stage of solution
nitriding, austenite grains containing approximately 1mass% nitrogen
nucleated at the material surface, and then they gradually grew into the
material with solution nitriding. EBSP measurement for the solution-nitrided
specimens revealed that some austenite grains have the crystallographic
orientations close to Kurdjumov-Sachs (K-S) relationship with the parent
ferrite grain; however, there were a lot of austenite grains with no
specific orientaiton relationship. This suggests that the crystallographic
orientation of the product phase is not fixed only by that of the parent
phase when it nucleates at specimen surface.
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