A constitutive model of twinning and detwinning for hexagonal close packed polycrystals

A new constitutive model to describe twinning and detwinning for polycrystalline materials with the hexagonal close packed (HCP) crystallographic structure is developed and implemented in the recently developed elastic viscoplastic self-consistent (EVPSC) polycrystal model. The new model is then applied to magnesium alloy Mg–3 Al–1 Zn (AZ31B) sheet under cyclic loadings and strain path changes. It is demonstrated that the new twinning model is able to capture key features associated with twinning and detwinning observed experimentally.