中文摘要：

镁合金在室温成形中存在着严重的回弹问题,为了获得准确的材料参数来对其回弹行为进行精确的预测和有效的控制,以AZ31B和AM60B镁合金板为研究对象,进行了单向拉伸试验,并对AZ31B进行了扫描电镜观察。采用加载-卸载-再加载的往复单向拉伸试验对镁合金板在卸载过程中的应力应变响应进行了重点分析,并讨论了卸载过程中的非弹性回复行为的变化规律。结果表明：AZ31B和AM60B镁合金板在卸载过程中表现出显著的非线性,卸载总应变回复包括弹性回复和非弹性回复两部分,非弹性回复随着塑性应变的增加呈短暂上升趋势后缓慢减小,最大占比达到24%左右。

英文摘要：

Magnesium alloys have severe springback problem when they are stamped at room temperature. In order to obtain correct material parameters for precise springback prediction and control,the AZ1 B and AM60 B magnesium sheets were taken as the research objects,the uniaxial tension experiments performed,and SEM observation was performed on AZ31 B. The response of stress and strain during unloading of magnesium alloy subject to loading-unloading-reloading tests was emphatically analyzed,and then,rule of the nonlinear unloading behavior was discussed in detail. The results show that magnesium alloys AZ31 B and AM60 B have significant nonlinear unloading behavior,and the total strain recovery during unloading consists of elastic and inelastic component. The percentage of the inelastic recovery in the total strain recovery first increases and then decreases with the increase of the plastic strain,and its max percentage can reach about 24%.