一种新型Mg-RE-Zn合金高温变形本构模型研究

Study on constitutive model of a new Mg-RE-Zn alloy during high temperature deformation

为研究一种新型Mg-RE-Zn合金的高温流变行为,对该合金进行应变速率分别为0.001、0.01、0.1和1 s^(-1),变形温度分别为250、300、350和400℃的高温拉伸实验。基于实验得到的应力、应变数据,综合考虑应变、应变速率和变形温度对流变应力的影响,构建了新型Mg-RE-Zn合金高温变形条件下改进的Zerilli-Armstrong模型和改进的Arrhenius-type本构模型。结果表明:在实验选取的变形条件下,合金的峰值流变应力随着应变速率的升高和温度的降低而增大,流变曲线显示出典型的动态再结晶特征。通过计算得到改进的Zerilli-Armstrong模型预测数据与实验数据的相关度R为0.962,平均相对误差Δ为10.79%;改进的Arrhenius-type模型预测数据与实验数据的相关度R为0.989,平均相对误差Δ为6.24%,表明构建的Arrhenius-type本构模型能够更好地描述该合金的高温流变行为。

To study the high-temperature rheological behavior of a new type of Mg-RE-Zn alloy,the high-temperature tensile experiments were conducted at the strain rate of 0.001,0.01,0.1 and 1 s^(-1) and the deformation temperature of 250,300,350 and 400℃.Based on the stress and strain data obtained from the experiment and comprehensively considering the effects of strain,strain rate and deformation temperature on the flow stress,an improved Zerilli-Armstrong model and an improved Arrhenius-type constitutive model under high temperature deformation conditions of the new Mg-RE-Zn alloy were constructed.The results show that under the experimental selected deformation conditions,the peak flow stress of alloy increases with the increase of strain rate and the decrease of temperature,and the rheological curve shows typical dynamic recrystallization characteristics.The correlation R between the predicted data of the improved Zerilli-Armstrong model and the experimental data is 0.962,and the average relative errorΔis 10.79%.The correlation between the predicted data and the experimental data of the improved Arrhenius-type model R is 0.989,the average relative errorΔis 6.24%,which indicates that the constructed Arrhenius-type constitutive model can better describe the high-temperature rheological behavior of the alloy.