Micromorphic approach to crystal plasticity and phase transformation

Abstract : Continuum crystal plasticity models are extended to incorporate the effect of the dislocation density tensor on material hardening. The approach is based on generalized continuum mechanics including strain gradient plasticity, Cosserat and micromorphic media. The applications deal with the effect of precipitate size in two-phase single crystals and to the Hall-Petch grain size effect in polycrystals. Some links between the micromorphic approach and phase field models are established. A coupling between phase field approach and elastoviscoplasticity constitutive equations is then presented and applied to the prediction of the influence of viscoplasticity on the kinetics of diffusive precipitate growth and morphology changes.