Constitutive modeling for dynamic recrystallization kinetics of Mg-4Zn-2Al-2Sn alloy

In order to have a better understanding of the hot deformation behavior of the as-solution-treated Mg-4Zn-2Sn-2Al (ZAT422) alloy, a series of compression experiments with a height reduction of 60% were performed in the temperature range of 498-648 K and the strain rate range of 0.01-5 s−1 on a Gleeble 3800 thermo-mechanical simulator. Based on the regression analysis by Arrhenius type equation and Avrami type equation of flow behavior, the activation energy of deformation of ZAT422 alloy was determined as 155.652 kJ/mol, and the constitutive equations for flow behavior and the dynamic recrystallization (DRX) kinetic model of ZAT422 alloy were established. Microstructure observation shows that when the temperature is as low as 498 K, the DRX is not completed as the true strain reaches 0.9163. However, with the temperature increasing to 648 K, the lower strain rate is more likely to result in some grains' abnormal growth.