Rozaliya Barabash

White microbeam diffraction from distorted crystals

We present a general description of white-beam (Laue) scattering from grains with dislocations. This approach is applied to examples with equal numbers of positive and negative Burger’s vectors (paired) and with unpaired dislocations of one sign (geometrically necessary). We find that streaking of the Laue reflections is sensitive to both long-range geometrical rotations introduced by unpaired edge dislocations and to local rotation fluctuations introduced by the total number of dislocations (paired and unpaired). We demonstrate the technique by analyzing the dislocation distribution in a nanoindented Cu single crystal.

Quantitative microdiffraction from deformed crystals with unpaired dislocations and dislocation walls

This article describes how unpaired dislocations alter white-beam Laue patterns for either isolated dislocations, dislocation walls, or combinations of dislocation walls and isolated dislocations. The intensity distribution of Laue diffraction is analyzed as a function of local misorientation. We show how to quantitatively determine the dislocation structure of single crystals and polycrystals with plastic deformation. The technique is applied to interpret the complicated plastic–elastic field in an iridium weld sample.

Polychromatic X-ray Microdiffraction Studies of Mesoscale Structure and Dynamics

Polychromatic X-ray microdiffraction is an emerging tool for studying mesoscale structure and dynamics. Crystalline phase, orientation (texture), elastic and plastic strain can be nondestructively mapped in three dimensions with good spatial and angular resolution. Local crystallographic orientation can be determined to approximately 0.01 degree and elastic strain tensor elements can be measured with a resolution of approximately 10(-4) or better. Complete strain tensor information can be obtained by augmenting polychromatic microdiffraction with a monochromatic measurement of one Laue-reflection energy. With differential-aperture depth profiling, volumes tens to hundreds of micrometers below the surface are accessible so that three-dimensional distributions of crystalline morphology including grain boundaries, triple points, second phases and inclusions can all be mapped. Volume elements below 0.25 microm3 are routinely resolved so that the grain boundary structure of most materials can be characterized. Here the theory, instrumentation and application of polychromatic microdiffraction are described.

Strain and dislocation gradients from diffraction : spatially-resolved local structure and defects

Diffraction Analysis of Defects - State of the Art X-Ray Laue Diffraction Microscopy in 3D at the Advanced Photon Source High Energy Transmission Laue Micro-Beam Diffraction XMAS: A Versatile Tool for Analyzing Synchrotron X-Ray Microdiffraction Data Laue Microdiffraction at ESRF 3D X-Ray Diffraction Microscopy Grain Centre Mapping - 3DXRD Measurements of Average Grain Characteristics Three Dimensional X-Ray Diffraction Imaging Techniques High Resolution Reciprocal Space Mapping for Characterizing Deformation Structures Reconstructing 2D & 3D Orientation Maps from White Beam Laue Energy-Variable X-Ray Diffraction for Studying Polycrystalline Materials with High Depth Resolution Microstructure Detail Extraction via EBSD: An Overview High Pressure Studies with Microdiffraction.

Study of twinning in alpha-Ti by EBSD and Laue microdiffraction

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Polychromatic Microdiffraction Characterization of Defect Gradients in Severely-Deformed Materials

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Microstructural characterization of polycrystalline materials by synchrotron X-rays

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