(1. 重庆大学 材料科学与工程学院，重庆 400044；
2. 国家镁合金材料工程技术研究中心，重庆 400045)
摘 要: 采用Gleeble-1500热/力模拟试验机进行压缩实验，研究Mg-2Zn-1Mn (ZM21)与Mg-6Zn-1Mn (ZM61)合金在变形温度523~723 K、应变速率0.01~10 s-1范围内的流变应力行为，并以热压缩实验为基础，建立两种合金的动态模型加工图，引入材料加工硬化率θ，结合θ—σ曲线拐点判据识别合金发生动态再结晶的临界应变εc。结果表明，ZM21与ZM61合金在热压缩过程中发生明显的动态回复与动态再结晶；随着Zn含量的增加，ZM61合金的变形激活能比ZM21合金的升高约20%，并且ZM61合金在高温变形时更容易出现失衡；两者发生动态再结晶的临界应变εc均随着应变速率的增加而升高，随变形温度的升高而降低。
关键字: 镁合金；热压缩；动态再结晶；临界应变
（1. College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China;
2. National Engineering Research Center for Magnesium Alloys, Chongqing 400045, China）
Abstract:The thermal compression behavior of Mg-2Zn-1Mn (ZM21) and Mg-6Zn-1Mn (ZM61) magnesium alloys was investigated by uniaxial compression tests on Gleeble-1500 thermal simulation test machine at the temperature ranging from 523 K to 723 K and strain rate ranging from 0.01 s-1 to 10 s-1. According to the experimental results, the hot processing maps based on the dynamic materials modeling were drawn. The critical strain εc that the dynamical recrystallization occurs was identified by introducing the hard working rate θ and inflection point of θ—σ curves under different deformation. The results show that the dynamic recovery and dynamic recrystallization occur obviously during hot compression of ZM21and ZM61 alloys. Compared with ZM21 alloy, the deformation activation energy of ZM61 alloy increases by 20% because of the increase of Zn content, and the ZM61 alloy is more unstable than ZM21 alloy. The critical strain εc of both alloys increases with the increase of strain rate and decreases with the increase of deformation temperature.
Key words: magnesium alloy; thermal compression; dynamic recrystallization; critical strain
