高温塑性变形行为的热压缩模拟
(中南大学 材料科学与工程学院，长沙 410083)
摘 要: 采用Gleeble−1500热压缩模拟试验机进行压缩实验，研究ZK60(0.9Y+0.3Nd)镁合金在变形温度623~773 K、应变速率0.001~1 s−1的范围内的变形行为，计算应力指数和变形激活能，并采用Zener-Hollomon参数法构建合金高温塑性变形的本构关系。结果表明：在实验变形条件下，合金的真应力—真应变曲线为动态再结晶型；在实验温度范围内，应力指数随着变形温度的升高而增大，变形激活能随着变形温度和应变速率的增加而增大。对比ZK60合金，ZK60(0.9 Y+0.3Nd)合金的变形激活能提高38%。
关键字: 塑性变形；热模拟；动态再结晶；镁合金
（School of Materials Science and Engineering, Central South University, Changsha 410083, China）
Abstract:The hot deformation behavior of ZK60(0.9Y+0.3Nd) magnesium alloy was investigated by hot compressive tests on Gleeble−1500 thermal simulation test machine in the temperatures range of 623−773 K and strain rate range of 0.001−1s−1. The stress exponent and the deformation activation energy at elevated temperatures (623−773 K) were calculated. The constitutive equation of the plastic deformation of ZK60(0.9Y+0.3Nd) alloy at elevated temperatures (623−773 K) was obtained by introducing Zener-Hollomon parameter. The results show that the true stress—strain curves of the alloy have dynamic recrystallization character under the present deformation conditions. In the temperature range of 623−773 K, the stress exponent increases with the increase of deformation temperature. The deformation activation energy changes with the increase of deformation temperature and strain rate. Compared with ZK60 alloy, the deformation activation energy of ZK60(0.9Y+0.3Nd) alloy increases by 38%.
Key words: plastic deformation; thermal simulation; dynamic recrystallization; magnesium alloy
