Crystal orientation changes: A comparison between a crystal plasticity finite element study and experimental results

Abstract

Tension tests on single-crystalline and bicrystalline austenitic stainless steel samples at ambient temperature and constant crosshead speed have been carried out. To understand the limits of crystal plasticity models in predicting the microstructural evolution process, simulation data were compared to experimentally observed crystal orientation evolution and strain analyses. The microstructure was captured after deformation by using electron backscatter diffraction and local strain analyses by digital image correlation. The initial grain orientation, sample geometry, boundary conditions and high-angle grain boundaries have enormous influences on the crystal orientation evolution. Strain gradients and rigid body rotation can be captured from the crystal plasticity model of Bassani & Wu. However, the description of the substructural fragmentation process lies beyond the capability of the model used. Slight modifications on the model by activation of slip systems and the implementation of a structural length scale delivers the experimentally observed substructures.