铸态稀土镁合金热变形应变补偿型本构模型

Constitutive Model by Strain Compensation of Thermal Deformation of AZ80 Alloy as Cast Condition

采用Gleeble/1500热模拟试验机,在变形温度300~420℃,应变速率0.0005~0.5 s-1,对铸态稀土AZ80合金进行高温热压缩试验,研究了该合金的高温流动应力应变变化规律,并建立了应变补偿的材料热变形Arrhenius本构关系模型。将计算结果与热模拟实验得到的应力应变曲线进行对比,结果比较吻合。鉴于应变对流动应力的影响,确定了峰值应力、变形温度和应变速率之间的关系,并获得了变形激活能和本构方程中材料常数随应变的变化规律。

At the deformation condition of deformation temperature of 300-420 ℃, strain rate of 0.0005-0.5 s1, the isothermal and constant strain rate compression test for RE-Mg alloy as cast condition was carried out by Gleeble-1500 thermal simulation testing machine. The discipline of flow stress of the alloy changing at high temperature was studied, and the Arrhenius constitutive relation model was established by strain compensation of thermal deformation of RE-Mg alloy. Compared calculated results and stress-strain curve obtained by thermal simulation experiment, the result is consistent. Considering the influence of strain on the flow stress, the relationship among peak stress, deformation temperature and strain rate was determined, and the discipline of deformation activation energy and material constant of constitutive equation changing with the strain can be gotten.