Non-proportionality of strain and coupling effects on dislocation distribution and ductility in ferritic steel polycrystals

Abstract

Non-proportionality of straining, initial texture and hardening have been investigated in a ferritic steel polycrystal within a crystal plasticity finite element framework. Two extreme forms of hardening are investigated; namely, isotropic latent-hardening and anisotropic self-hardening. Dislocation density evolutions on all independent slip systems have been calculated in order to investigate the establishment of dislocation distributions and evaluate their dependence on non-proportionality, hardening, texture and predicted ductility. The results show that non-proportionality effects are more pronounced under isotropic latenthardening as opposed to anisotropic self-hardening especially under non-proportional uniaxial strains.