Showing papers on "Electron backscatter diffraction published in 2000"

Electron Backscatter Diffraction in Materials Science

Abstract: List of Contributors. 1. The Development of Automated Diffraction in Scanning and Transmission Electron Microscopy D.J. Dingley. 2. Theoretical Framework for Electron Backscatter Diffraction V. Randle. 3. Representation of Texture in Orientation Space K. Rajan. 4. Rodriques-Frank Representations of Crystallographic Texture K. Rajan. 5. Fundamentals of Automated EBSD S.I. Wright. 6. Studies on the Accuracy of Electron Backscatter Diffraction Measurements M.C. Demirel, B.S. El-Dasher, B.L. Adams, A.D. Rollett. 7. Phase Identification Using Electron Backscatter Diffraction in the Scanning Electron Microscope J.R. Michael. 8. Three-Dimensional Orientation Imaging D.J. Jensen. 9. Automated Electron Backscatter Diffraction: Present State and Prospects R.A. Schwarzer. 10. EBSD: Buying a Systems A. Eades. 11. Hardware and Software Optimization for Orientation Mapping and Phase Identification P.P. Camus. 12. An Automated EBSD Acquisition and Processing System P. Rolland, K.G. Dicks. 13. Advanced Software Capabilities for Automated EBSD S.I. Wright, D.P. Field, D.J. Dingley. 14. Strategies for Analysis of EBSD Datasets W.E. King, J.S. Stolken, M. Kumar, A.J. Schwartz. 15. Structure-Property Relations: EBSD-Based Materials-Sensitive Design B.L. Adams, B.L. Henrie, L.L. Howell, R.J. Balling. 16. Use of EBSD Data in Mesoscale Numerical Analyses R. Becker, H. Weiland. 17. Characterization of Deformed Microstructures D.P. Field, H. Weiland. 18. Anisotropic Plasticity Modeling Incorporating EBSD Characterization of Tantalum and Zirconium J.F. Bingert, G.C. Kaschner, T.A. Mason, P.J. Maudlin, G.T. Gray III. 19. Measuring Strains Using Electron Backscatter Diffraction A.J. Wilkinson. 20. Mapping Residual Plastic Strain in Materials Using Electron Backscatter Diffraction E.M. Lehockey, Yang-Pi Lin, O.E. Lepik. 21.EBSD Contra TEM Characterization of a Deformed Aluminum Single Crystal Xiaoxu Huang, D.J. Jensen. 22. Continuous Recrystallization and Grain Boundaries in a Superplastic Aluminum Alloy T.R. McNelley. 23. Analysis of Facets and Other Surfaces Using Electron Backscatter Diffraction V. Randle. 24. EBSD of Ceramic Materials J.K. Farrer, J.R. Michael, C.B. Carter. 25. Grain Boundary Character Based Design of Polycrystalline High Temperature Superconducting Wires A. Goyal. Index.

Introduction to texture analysis : macrotexture, microtexture and orientation mapping

Abstract: Part I: Fundamental Issues Introduction The Classical Approach to Texture The Modern Approach to Texture: Microtexture A Guide to the Book Descriptors of Orientation Crystal Structures and Crystal Symmetries Transformation between Coordinate Systems: The Rotation Matrix The "Ideal Orientation" (Miller or Miller-Bravais Indices) Notation The Reference Sphere, Pole Figure, and Inverse Pole Figure The Euler Angles and Euler Space The Angle/Axis of Rotation and Cylindrical Angle/Axis Space The Rodrigues Vector and Rodrigues Space Application of Diffraction to Texture Analysis Diffraction of Radiation and Bragg's Law Structure Factor Laue and Debye-Scherrer Methods Absorption and Depth of Penetration Characteristics of Radiations Used for Texture Analysis Part II: Macrotexture Analysis Macrotexture Measurements Principle of Pole Figure Measurement X-Ray Diffraction Methods Neutron Diffraction Methods Texture Measurements in Low-Symmetry and Multiphase Materials Sample Preparation Evaluation and Representation of Macrotexture Data Pole Figure and Inverse Pole Figure Determination of the Orientation Distribution Function from Pole Figure Data Representation and Display of Texture in Euler Space Examples of Typical Textures in Metals Part III: Microtexture Analysis The Kikuchi Diffraction Pattern The Kikuchi Diffraction Pattern Quantitative Evaluation of the Kikuchi Pattern Pattern Quality Scanning Electron Microscopy-Based Techniques Micro-Kossel Technique Electron Channeling Diffraction and Selected-Area Channeling Evolution of Electron Backscatter Diffraction EBSD Specimen Preparation Experimental Considerations for EBSD Calibration of an EBSD System Operation of an EBSD System and Primary Data Output Transmission Electron Microscopy-Based Techniques High-Resolution Electron Microscopy Selected Area Diffraction Kikuchi Patterns, Microdiffraction, and Convergent Beam Electron Diffraction Evaluation and Representation of Microtexture Data Representation of Orientations in a Pole Figure or Inverse Pole Figure Representation of Orientations in Euler Space Representation of Orientations in Rodrigues Space General Representation of Misorientation Data Representation of Misorientations in Three-Dimensional Spaces Normalization and Evaluation of the Misorientation Distribution Function Extraction of Quantified Data Orientation Microscopy and Orientation Mapping Historical Evolution Orientation Microscopy Orientation Mapping and Its Applications Orientation Microscopy in the TEM Crystallographic Analysis of Interfaces, Surfaces, and Connectivity Crystallographic Analysis of Grain Boundaries Crystallographic Analysis of Surfaces Orientation Connectivity and Spatial Distribution Orientation Relationships between Phases Synchrotron Radiation, Nondiffraction Techniques, and Comparisons between Methods Texture Analysis by Synchrotron Radiation Texture Analysis by Nondiffraction Techniques Appendices Glossary References General Bibliography Index

Electron backscattering diffraction study of acicular ferrite, bainite, and martensite steel microstructures

Abstract: This study deals with acicular ferrite, bainite, and martensite microstructures observed in three low alloy steels. Electron backscattering diffraction (EBSD) was used to assess crystallographic features of these microstructures. In each area studied by EBSD mapping, ‘crystallographic packets’ defined as clusters of points sharing the same crystallographic orientation were compared with ‘morphological packets’ observed in the corresponding light micrograph. Microtexture studies suggested that acicular ferrite and upper bainite grow with Nishiyama– Wassermann relationships with the parent austenite phase, whereas lower bainite and martensite consist of highly intricate packets having Kurdjumov–Sachs relationships with the parent phase. In all cases three highly misoriented texture components were found within each former austenite grain. Electron backscattering diffraction also gave information about the cleavage and intergranular reverse temper embrittlement fracture mechanisms of these steels. In...

Defect and Microstructure Analysis by Diffraction

Abstract: Introduction to Defect and Microstructure Analysis or the Analysis of Real-Structure Some Applications of the Kinematical Theory of X-ray Diffraction Profile Fitting and Analytical Functions Effects of Instrument Function, Crystallite Size, and Strain on Reflection Profiles Use of Pattern Decomposition or Simulation to Study Microstructure: theoretical considerations Classical Treatment of Line Profiles Influenced by Strain, Small Size, and Stacking Faults Voigt-Function Model in Diffraction Line-Broadening Analysis X-Ray Analysis of Precipitation Related Crystals with Dislocation Substructure The Dislocation Based Model of Strain Broadening in X-Ray Line-Profile Analysis Diffraction-Line Broadening Analysis of Dislocation Configurations Diffraction-Line Broadening Analysis of Strain Fields in Crystalline Solids Paracrystallinity The Model of the Paracrystal and its Application to Polymers Effect of Planar Defects in Crystal on the Position and Profile of Powder Diffraction Line Effect of Stacking Disorder on the Profile of the Powder Diffraction Line Crystallite Statistics and Accuracy in Powder Diffraction Intensity Measurements Reciprocal Space Mapping and Ultra-High Resolution Diffraction of Polycrystalline Materials X-Ray Analysis of The Inhomogeneous Stress State Texture Analysis Texture Effects in Powder Diffraction and their Correction by Simple Empirical Functions Accounting For Size and Microstrain in Whole Powder Pattern Fitting Modelling of Texture in Whole Pattern Fitting A New Whole Powder Pattern Fitting Approach The Role of Whole-Pattern Databases in Materials Science Restoration and Preprocessing of Physical Profiles from Measured Data Towards Higher Resolution: A Mathematical Approach Use of Pattern Decomposition to Study Microstructure: Practical Aspects and Applications X-Ray Diffraction Broadening Effects in Materials Characterization Crystal Size and Distortion Parameters in Fibres using WAXS Pressure Induced Profile Change of Energy Dispersive Diffraction

Thermal and Grain Structure Simulation in a Land-based Turbine Blade Directionally Solidified with the Liquid Metal Cooling Process

Abstract: The thermal field and the grain structure of a cored superalloy turbine blade, which has been directionally solidified with the liquid metal cooling (LMC) process, has been simulated in three dimensions using a cellular automaton (CA) coupled with finite-element (CAFE) model. The cooling induced by the liquid aluminum bath has been replaced by a heat-transfer coefficient, whose temperature- and time-dependence has been adjusted on the basis of natural convection simulations and dimensionless analyses. The simulated grain structure and crystallographic texture have been compared with the microstructure, and the electron back-scattered diffraction (EBSD) results were obtained for a real blade. In both the experiment and the simulation, it has been found that the grains do not exhibit a well-defined texture, even near the top of the blade, mainly as a result of a concave liquidus surface. In order to improve the texture and decrease the number of stray crystals, the LMC process was then optimized by changing several parameters. The baffle geometry, the liquid bath level, and the thermal conductivity of the ceramic mold were found to be the dominant parameters. Using the optimized design, the effect of the withdrawal rate on the resulting grain structure was investigated.

Crystal plasticity of natural garnet: New microstructural evidence

Abstract: Scanning electron microscope (SEM) orientation contrast images of mantle nodules show that garnets contain cellular domains of different crystallographic orientation. Electron backscatter diffraction shows small crystallographic mismatches (

Structures of nanometre-size crystals determined from selected-area electron diffraction data

Abstract: The structure of a new modification of Ti2Se, the β-phase, and several related inorganic crystal structures containing elements with atomic numbers between 16 and 40 have been solved by quasi-automatic direct methods from single-crystal electron diffraction patterns of nanometre-size crystals, using the kinematical aproxi­mation. The crystals were several thousand times smaller than the minimum size required for single-crystal X-ray diffraction. Atomic coordinates were found with an average accuracy of 0.2 A or better. Experimental data were obtained by standardized techniques for recording and quantifying electron diffraction patterns. The SIR97 program for solving crystal structures from three-dimensional X-ray diffraction data by direct methods was modified to work also with two-dimensional electron diffraction data.

High Resolution EBSD Analysis of the Grain Structure in an AA2024 Friction Stir Weld

Abstract: The grain structures formed during friction stir welding of a typical aluminium aerospace alloy have been studied by high resolution EBSD analysis. The grain structures reflect the local deformation conditions, and due to the high temperatures and strains, show characteristics typical of different stages of dynamic recrystallisation. The large strains and high density of second phase particles in the nugget zone result in a very fine 2-3 μm equiaxed grain size. There is an abrupt transition in grain structure between the nugget and the TMAZ at the side of the weld. A very fine grain structure was also observed near to the top surface of the weld that was in contact with the tool shoulder. The nugget zone, onion ring structure was attributed to bands of different densities of second phase particles, rather than any significant difference in the local grain structure or texture.

Microtexture and electromigration-induced drift in electroplated damascene Cu

Abstract: In this work, the electromigration (EM) performance of electroplated damascene Cu is investigated by drift experiments on Blech-type test structures in both polycrystalline and bamboo microstructures. For the first, microtexture data were obtained from electron backscatter diffraction as well. While both bonding areas and 10 μm wide lines were found to have a predominantly random grain orientation, the drift studies indicated the importance of strongly segregating impurities in controlling Cu grain-boundary EM. For the bamboo lines, the impact of different barrier layers has been investigated, comparing Ta, TaN, and TiN. Drift was shown to proceed in all cases at the metallic Cu barrier interface, but faster for the Ta as compared to the TaN and TiN barriers. Cu drift data were finally compared to available literature results and to our previous drift studies on Al(Cu).

Advances in SEM–based diffraction studies of defects and strains in semiconductors

Abstract: Two scanning electron microscope (SEM)-based diffraction techniques, i.e. electron channelling contrast imaging (ECCI) and electron back-scatter diffraction (EBSD) are used to study lattice defect and local elastic strain distributions in Si1-xGe(x) epilayers grown on Si substrates patterned with mesas. The ECCI technique allows the misfit dislocations to be imaged in bulk samples. The misfit dislocations caused plastic relaxation of the strain in planar regions between mesas and in the wider mesas. In the narrower mesas the removal of lateral constraint at the mesa side faces had reduced the stress sufficiently to suppress the propagation of dislocations parallel to the closely spaced side faces. The measurements of small changes in the positions of two zone axes in EBSD patterns caused by variations in the local strain field were used to determine the strains and rotations making up the generalized plane strain tensor describing the deformation in the long mesa structures. The strain sensitivity of the method was determined to be approximately +/- 2 x 10(-4). Distributions of strains and rotations across mesas of several dimensions are reported and differ significantly between mesa for which the mesas width to epilayer thickness is high and low.

High‐temperature plastic deformation of quartz‐plagioclase multilayers by layer‐normal compression

Abstract: It is a common practice in rheological modeling to take the extrapolated compressive flow strengths of quartzite and plagioclase rock as the bulk flow strengths of the upper and lower continental crusts, respectively. Such a practice implies that the bulk flow strength of polyphase rocks is identical to that of the pure weak phase. To test this assumption, we performed deformation experiments on synthetic layered and particulate quartz-anorthite (50∶50) composites and aggregates of the end-members in a Paterson gas-medium apparatus at a confining pressure of 300 MPa, a constant strain rate of 10−5 s−1 and temperatures from 1273 to 1473 K. Under these conditions, anorthite deforms by recrystallization-accommodated dislocation creep, while quartz is semibrittle. Electron backscatter diffraction measurements show a strong lattice-preferred orientation (LPO) of anorthite developed in deformed specimens, and the LPO pattern is interpreted as a result of dislocation slip on the (010)[100] system. Our experimental results show that the bulk flow strength of layered composites increases with decreasing thickness of the layers. Thinlayered composites are significantly stronger than pure anorthite aggregates and a homogeneous quartz-anorthite mixture (i.e., particulate composites) with the same modal composition but weaker than pure quartz aggregates. Our experimental results together with the theoretical overview presented previously in the materials science literature demonstrate that (1) compressive flow strength of a polyphase rock cannot be represented by that of the weak phase and (2) thin-layered rocks compressed normal to the layering are rheologically stronger than homogeneous, isotropic mixtures under the same deformation conditions. Thus weak-phase-based rheology will lead to an underestimation of the bulk flow strength of the continental crust in which polyphase rocks dominate.

Fabric and seismic properties of carrara marble mylonite

Abstract: Shear deformation in calcite-rich rocks can produce strong lattice preferred orientations (LPO), which result in a high anisotropy of bulk seismic properties because of the high elastic anisotropy of calcite (32% Vp anisotropy). Deformed rocks often show also strong shape preferred orientations (SPO). Theories for averaging the elastic properties have not yet satisfactorily predicted the contribution to the seismic anisotropy caused by the SPO alone. A calcite mylonite from Carrara (Italy) was investigated, which is characterised by a strong SPO and a weak LPO. It was composed of about 80% calcite, then white mica, quartz and hematite. Flattening of mica and of calcite grains defined the mylonitic foliation, and elongation of calcite grains defined the lineation. On average calcite grains have aspect ratios of about 2.5:1.6:1, and grain sizes of about 10 μm. At 400 MPa confining pressure, the measured Vp (km/s) parallel to the lineation (X direction) was highest (6.63), lower in the intermediate Y direction (6.47); the Vp normal to the foliation (Z direction) was lowest (6.30). This yielded a Vp anisotropy of 5%. The LPO, determined by automated electron backscatter diffraction (EBSD), was very weak (texture index 1.1), with intensities between 0.6 and 1.6 m.r.d. in the c-axis pole figure. Extrapolation of the texture index to an infinite number of orientation measurements indicated that the observed variations were mostly random noise in the orientation distributions and that the bulk rock texture was random. The Vp anisotropy of the Voigt, Reuss and Hill averages calculated from this calcite LPO is predicted to be close to zero. Adding 5% of muscovite with (001) perfectly aligned parallel to the foliation, we calculated a total anisotropy of 2.8%. The anisotropy calculated for the special directions X, Y and Z remained at 2.6% only. It was concluded that the measured seismic anisotropy cannot be explained by the LPO of calcite and by 5% of mica alone. It is also attributed to the strong SPO and to further grain boundary effects.