Mg−4Zn−2Al−2Sn合金动态再结晶行为动力学数值模拟

摘要

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.%利用Gleeble 3800热模拟试验机研究ZAT422合金在变形温度为498～648 K、应变速率为0.01～5 s?1、压下量为60％的热变形行为.基于Arrhenius方程和Avramit方程对该合金流变行为进行分析,得到变形激活能为155.652 kJ/mol,并构建该合金的本构方程和动态再结晶模型.组织观察表明:变形温度低至498 K,真应变为0.9163时,合金发生不完全动态再结晶;温度升高至648 K时,较低的应变速率易导致部分晶粒的异常长大.