Modelling the temperature and texture effects on the deformation mechanisms of magnesium alloy AZ31

Abstract

A temperature sensitive viscoplastic self-consistent (VPSC) model is developed to investigate the temperature and texture effects on the deformation mechanisms of a hot-rolled magnesium (Mg) alloy AZ31. A novel approach to incorporate the drag stress and dislocation-dislocation interactions as temperature dependent parameters is conducted in this paper. In addition, the model is coupled with a composite grain twin model, and dislocation density based hardening laws to predict the activation of the deformation modes participating in strain accommodation in Mg alloys: 〈a〉 basal slip, 〈a〉 prismatic slip, and 〈c+a〉 pyramidal slip, {101¯2} tensile twinning, and {101¯1} compressive twinning. The model is validated against an experimental study, realised on a hot-rolled AZ31 Mg alloy deformed at temperatures ranging from 25°C to 200°C under uniaxial tensile loads parallel to, perpendicular to, and 45° offset from the rolling direction of the material. The results of the simulations are in agreement with the experimental data in terms of hardening behaviour, deformation activities, and texture evolution. The presence of dynamic recrystallisation, which is observed experimentally at higher temperatures, shows the limitations of the present model.