Automated indexing for texture and strain measurement with broad-bandpass x-ray microbeams

Methods are derived for measuring local strain, stress, and crystallographic texture (orientation) in polycrystalline samples when 1-10 grains are simultaneously illuminated by an energy scanable or broad-bandpass x-ray beam. The orientation and unit-cell shape for each illuminated grain can be determined from the diffracted directions of four Bragg reflections. The unit-cell volume is determined by measuring the energy (wavelength) of one reflection. The methods derived include an algorithm for simultaneously indexing the reflections from overlapping crystal Laue patterns and for determining the average strain and stress tensor of each grain. This approach allows measurements of the local strain and stress tensors which are impractical with traditional techniques. (C) 1999 American Institute of Physics. [S0021-8979(99)07921-9].