TC4-DT合金的超塑性变形及其本构方程

Superplastic Deformation and Constitutive Equations of TC4-DT Alloy

采用CMT4104电子万能拉伸试验机分别进行温度为870℃,应变速率为3.3×10-4s-1的恒应变速率和温度为850~890℃,应变速率为3.3×10-5~3.3×10-3s-1的应变速率循环法超塑性拉伸实验。结果表明:在变形过程中存在动态回复与动态再结晶现象,并采用Avrami方程描述了动态再结晶动力学行为;基于应变速率循环法获得了TC4-DT合金的本构模型,再通过1stopt软件加以回归拟合,得到较为精确的TC4-DT合金超塑性变形本构方程。

Superplastic deformation tests of TC4-DT alloy were performed with a superplastic tensile testing machine CMT4104.The constant strain rate method and the strain rate circulation method were used.In the constant strain rate test,the strain rate was fixed at 3.3×10-4s-1 and the temperature was fixed at 870℃;in the strain rate circulation test,the strain rates were tuned from3.3×10-5s-1 to 3.3×10-3s-1 and the temperature was from 850℃to 890℃respectively.The results show that dynamic recovery and dynamic recrystallization occur during the superplastic deformation and the dynamic recrystallization kinetics behavior can be described by Avrami equation.The experimental results of the strain rate circulation method were used to establish the constitutive relationship of the TC4-DT alloy.Regression analysis was carried out with the 1stopt software and a precise constitutive equation for superplastic deformation of the TC4-DT alloy is obtained.