Al-9.39Zn-1.92Mg-1.98Cu合金的热变形力学行为及其物理模型（英文）

Hot Compressive Deformation Behavior and Constitutive Equation of Al-9.39Zn-1.92Mg-1.98Cu Alloy

对Al-9.39Zn-1.92Mg-1.98Cu合金做等温热模拟压缩实验,变形温度为300~460℃,应变速率为0.001~10s-1,变形量为60%。结果表明:变形时,合金的流变应力随着变形温度的降低或应变速率的增大而增大。由于热变形时存在摩擦影响,对流变应力曲线进行摩擦修正。修正后的应力值低于实验值,摩擦力对流变应力的影响程度随着温度的降低和应变速率的增大而增大。基于经典的Arrhenius方程,考虑应变量对材料常数(α,n,Q和A)的影响,构建该合金在热变形时的本构方程。评价改进的本构方程预测能力,发现流变应力值与实测值吻合度较高,其相关度高达99.6%。

Hot compression tests for the Al-9.39 Zn-1.92 Mg-1.98 Cu alloy were carried out at the temperature ranging from 300?C to 460?C and the strain rate ranging from 0.001 s-1 to 1 s-1,and the height reduction degree was 70%.The flow stress was corrected because of the effect of friction.Results show the flow stress decreases with increasing the temperature or decreasing the strain rate.The friction effect becomes more and more obvious with increasing the temperature and decreasing the strain rate.A revised constitutive equation considering the influence of strain is established based on the Arrhenius-type model.Comparing the experimental and predicted flow stresses,the revised constitutive equation has higher accuracy.Their correlation coefficient and average absolute relative error is 0.996 and 2.45%,respectively.