Thermal activation based constitutive model for high-temperature dynamic deformation of AZ31B magnesium alloy

Abstract

Based on the existing experimental results of dynamic deformation at room temperature [1], a high-temperature dynamic test and a few supplementary microstructure observations by using an optical microscope were performed. Based on these experimental results, a thermal-activation-based dynamic constitutive model was proposed to describe the temperature-dependent dynamic deformation of an extruded AZ31B magnesium alloy. In the proposed model, both dislocation slipping and twinning were taken as shear movements with fixed shear planes and directions but with different thermodynamic features. Then, the total flow stress was divided into two parts, i.e., non-thermally and thermally activated ones. In addition, the effects of applied strain, strain rate, and temperature on the dynamic deformation of the extruded AZ31B magnesium alloy were incorporated into the proposed constitutive model. It is demonstrated that the flow stresses predicted by the proposed model show good agreement with the experimental results.