Computation of virtual X-ray diffraction patterns from discrete dislocation structures

Abstract

A computational method to generate virtual micro-Laue X-ray diffraction patterns from discrete dislocation representations is presented. In order to capture elastic strain and rotation heterogeneities in space, the method takes a two-step approach, whereby the deformation gradient field is first evaluated at a set of sampling points throughout the volume, after which the diffracting vectors at each sampling point are ray-traced and their intensities are integrated to produce the resulting diffraction patterns. A non-singular formulation for the deformation gradient is developed to avoid numerical artifacts arising when sampling near dislocation cores. As an example, the method is applied to compute virtual diffraction peaks on a large scale strain-hardened microstructure in single crystal copper obtained from a dislocation dynamics simulation.