Influence of material parameters on modeling plastic deformation of Mg alloys

Plastic deformation of HCP metals involves several deformation modes. The threshold stresses τs for the slip and twinning systems, are parameters determined in crystal plasticity models by fitting stress-strain curves. Four deformation paths were selected to activate four different deformation modes and determine the parameters in the VPSC. Experiments and simulations were conducted on a plate with a strong basal texture. It was found that changing the threshold stresses τs for basal slip has a limited effect on the predicted flow stress, because the flow stress is strongly dependent on the highest threshold stresses τs among the activated deformation modes. The influence of the variation of threshold stresses τs on plastic anisotropy was investigated. Only in plane tension anisotropy is strongly dependent on the relative threshold stresses τs, so r-value can be used efficiently to determine the material parameters.