Crystal Plasticity Modeling of the Slip Systems Activity in Mg Alloys at Higher Temperatures

Understanding the role of the slip systems and their evolution with temperature is critical to the correct simulation of the mechanical behavior of magnesium alloys. In this paper, relations are proposed for evolution of the CRSS values of different slip systems and strain-rate sensitivity factor, stating them as functions of temperature and strain-rate. These relations are used in conjunction with the Crystal Plasticity Finite Element (CPFE) model for prediction of stress-strain curves and r-values at elevated temperatures (75°C to 250°C). The new relations can predict the decrease in stress level, the anisotropy of the material, and the decrease in the difference between the r-values in the RD and the TD with the increase in temperature. The results confirm the trends predicted with Taylor-type and VPSC models. In particular, they confirm the high activity of the <c+a> slip systems at higher temperatures.