14 research outputs found
Evolution of dislocation structures following a change in loading conditions studied by in situ high resolution reciprocal space mapping
Multigrain indexing of unknown multiphase materials
A multigrain indexing algorithm for use with samples comprising an arbitrary number of known or unknown phases is presented. No a priori crystallographic knowledge is required. The algorithm applies to data acquired with a monochromatic beam and a conventional two-dimensional detector for diffraction. Initially, candidate grains are found by searching for crystallographic planes, using a Dirac comb convoluted with a box function as a filter. Next, candidate grains are validated and the unit cell is optimized. The algorithm is validated by simulations. Simulations of 500 cementite grains and âź100 reflections per grain resulted in 99.2% of all grains being indexed correctly and 99.5% of the reflections becoming associated with the right grain. Simulations with 200 grains associated with four mineral phases and 50â700 reflections per grain resulted in 99.9% of all grains being indexed correctly and 99.9% of the reflections becoming associated with the right grain. The main limitation is in terms of overlap of diffraction spots and computing time. Potential areas of use include three-dimensional grain mapping, structural solution and refinement studies of complex samples, and studies of dilute phases
Identifying individual subgrains in evolving deformation structures by high angular resolution X-ray diffraction
Advances in characterization of deformation structures by high resolution reciprocal space mapping
High-Resolution Single-Grain Diffraction of Polycrystalline Materials
Polycrystalline bulk materials are ubiquitous in everyday life, including biological, geological, and engineered structural and functional materials. Their fundamental units are individual grains, which are characterized by their microstructure; i.e., the arrangement of lattice defects. The microstructure usually influences the materials properties critically