Structural refinements of the individual grains within polycrystals and powders

Abstract

A method is presented for simultaneous structural refinement of up to several hundred grains inside powders or polycrystals. The method is based on the use of hard X-rays and the indexing programGRAINDEX, where grain orientations are found by scanning in Euler space. Conventional experimental setups and refinement programs for single-crystal work can be applied. The method is validated by a study of a sintered plate of α-Al2O3, containing of the order of 1500 grains in the gauge volume. 57 of the largest grains were refined with respect to the Alzand Oxpositions as well as the isotropic atomic displacement parameters. TheR1 values were 3.4% and 3.8% for the grain average and the best grain, respectively. A discussion of the potential of the method is presented, as well as the main limitation: grain size and overlap of diffraction spots.