Self-consistent modelling and the evaluation of lattice deformation in a polycrystalline austenitic stainless steel

Individual anisotropic grains within a polycrystalline material exhibit different micro-mechanical responses for a given applied macroscopic stress, leading to a variation in the meso-scale intragranular lattice strain. Despite various experimental data for the lattice strain evolution measured by neutron diffraction, a physical understanding of how the lattice strain evolves during plastic flow is still incomplete. In this study, a self-consistent model is established, taking into account detailed dislocation kinetics and its influence on different evolution processes of the dislocation distribution on different crystallographic planes of each grain within a polycrystalline material. The model is used to evaluate the micro-mechanical behaviour of F.C.C. polycrystalline austenitic stainless steels. Predictions of the lattice strain developed within individual grains of a polycrystal are compared with experimental results obtained using neutron diffraction. This model captures the major trends in the evolution of the lattice strains and provides an explanation and interpretation of the internal processes that most influence the observed response