中文摘要：

在应变速率为1×10-3~1 s-1、温度为300~450℃条件下,采用Gleeble-3500型热模拟机对Mg-1.3Zn-1.7Ca（质量分数,%）镁合金（ZX115）进行单轴热压缩实验;通过分析ZX115镁合金的真应力-真应变曲线,探讨变形温度和应变速率对其流变曲线中峰值应力、峰值应变及Zener-Hollomom参数的影响,建立描述该合金高温压缩变形的本构方程。将本构方程应用于有限元分析软件DEFORM 3D中,并对ZX115镁合金热压缩过程进行数值模拟,利用后处理程序,分析工件内部的应变速率场、应变场和温度场变化。研究表明：温度越高或应变速率越低时,流变曲线所达到的峰值应力越小,而在相同的应变速率下,峰值应变也随着变形温度的升高而明显减小;ZX115合金热压缩过程具有明显的变形不均匀性,为了合理控制变形后的再结晶晶粒尺寸,可适当降低形变温度和应变速率。

英文摘要：

The hot compressions of Mg-l.3Zn-l.7Ca （mass fraction, %）magnesium alloy （ZXll5） were carried out on Gleeble-3500 thermal simulator at a strain rate of 1 × 10-3-1 s-1 and temperature range of 300-450 ℃. Based on the true stress-strain curves of ZX115 magnesium alloy obtained from experiments, the effects of deformation temperatures and strain rates on the peak stress, peak strain and Zener-Hollomon parameter were discussed, and the constitutive equations were established to describe the hot compression of ZX115 magnesium alloy. These constitutive equations were applied into finite element analysis software DEFORM 3D and then the hot compressions of ZXll5 magnesium alloy were simulated. The variation and distribution of strain rate, strain and temperature in the compressed workpiece were analyzed by the post-processing procedures. The results show that peak stress decreases with increasing the deformation temperature or decreasing the strain rate, and the peak strain decreases with increasing the temperature under a given strain rate. The hot compressions of ZX 115 magnesium alloy exhibits a nonuniform characteristic. In order to control the recrystallized grain size, the deformation temperature and strain rate should be necessarily decreased.