Mg-13Gd-4Y-2Zn-0.5Zr合金形变软化行为及本构方程建立

使用型号为Gleeble-3500的热压缩实验机进行热压缩实验,在实验中调控温度和应变速率,绘制流变应力曲线图并进行分析。对Mg-13Gd-4Y-2Zn-0.5Zr合金在温度为360~480℃、应变速率为0.001~1 s^-1、并且热压缩试样的最大变形程度为60%条件下的形变软化现象进行了研究。经研究发现,Mg-13Gd-4Y-2Zn-0.5Zr合金的形变软化行为主要受其在不同变形条件下的动态再结晶行为的影响。设定材料常数α、n、A和Q与应变构建影响关系,将应变考虑在内后,建立了Mg-13Gd-4Y-2Zn-0.5Zr合金本构方程,其平均变形激活能为232.54 kJ·mol^-1。进行了误差检验,得到的峰值应力的实验值与计算值的平均相对误差的绝对值仅为5.5%,说明了建立的本构模型精度较高。

Deformation softening behavior and establishment of constitutive model for Mg-13Gd-4Y-2Zn-0.5Zr alloy

The hot compression experiment was carried out by using the hot compression machine Gleeble-3500.The temperature and strain rate were controlled and the flow stress curves were plotted and analyzed in experiments.The deformation softening phenomenon of Mg-13Gd-4Y-2Zn-0.5Zr alloy was studied under the conditions that the temperature was 360-480℃,strain rate was 0.001-1 s^-1 and the maximum deformation degree of hot compression specimen was 60%.The results show that the deformation softening behavior of Mg-13Gd-4Y-2Zn-0.5Zr alloy was mainly affected by its dynamic recrystallization behavior under different deformation conditions.The relationships between the material constants ofα,n,A and Q with the strain were set up.After taking the strain into account,the constitutive equation of Mg-13Gd-4Y-2Zn-0.5Zr alloy was established,and the average deformation activation energy was 232.54 kJ·mol-1.The error test was carried out,and the absolute value of the average relative error for peak stress between the experimental value and the calculated value is only 5.5%.The accuracy of the constitutive model is high.