Finite element simulations of coherent diffraction in elastoplastic polycrystalline aggregates
Résumé
This work ties some crystal plasticity continuum mechanics computations with the diffraction theory. This allows one to predict coherent X-ray diffraction (CXD) patterns in reciprocal space in a polycrystalline specimen. When the sample deforms elastically, the full displacement field can be used to simulate CXD patterns, but it is no longer possible, as soon as plasticity develops within the considered grains. An approximate elastic displacement field, based on a first order Taylor expansion of the elastic deformation field near the center of the grain, is used to extend the predictions in the plastic regime. It is shown that using such a field leads to more realistic CXD patterns and therefore this approach could be useful to interpret coherent diffraction experiments in the future.