Modified constitutive behavior model of Mg-10Gd-3Y-0.4Zr alloy during high-temperature deformation process

To investigate the flow behavior of Mg-10Gd-3Y-0.4Zr magnesium alloy during high-temperature deformation, the thermal compression experiments were conducted in the temperature range of 573-773 K and strain rate range of 0.001-1.0 s(-1). The experimental results showed that the flow stress decreases with the increase in temperature and decrease in strain rate. The variation of rheological stress was related to the strain change and the improved Arrhenius constitutive equation considering the strain compensation was established. However, the Arrhenius model with strain compensation showed obvious deviation in the true stress-strain curves at low temperature and high strain rate. The error analysis shows that the material parameters in Arrhenius model were not only related to strain, but also to strain rate and deformation temperature. Therefore, a modified Arrhenius-type constitutive model was established by considering the relationship between the material parameters and the forming parameters in high-temperature compression by comparing the calculated stress in the modified model with the experimental stress, the modified Arrhenius model established in this study can accurately predict the rheological stress of Mg-10Gd-3Y-0.4Zr magnesium alloy in all conditions during the high-temperature compression.