(中国工程物理研究院，绵阳 621900)
摘 要: 采用热物理模拟试验机研究V-5Cr-5Ti在变形温度为1150~1400 ℃和应变速率为0.001~1 s-1条件下的热变形行为。采用双曲正弦函数建立V-5Cr-5Ti合金高温条件下的本构方程，通过六次多项式拟合的方法将应变引入到本构方程中。结果表明：V-5Cr-5Ti合金真应力-应变曲线表现出动态再结晶和动态回复两种软化机制。流变应力随着应变速率的增加而增大，随温度的升高而减小。采用应变的六次多项式拟合得到的本构关系中，流变应力预测值与实验值吻合较好，绝大多数(94%)情况下预测的误差小于6.4%，平均相对误差仅为2.84%。
关键字: V-5Cr-5Ti；热压缩；本构方程；流变应力
（China Academy of Engineering Physics, Mianyang 621900, China）
Abstract:The flow stress behaviors of V-5Cr-5Ti alloy were investigated at the temperatures of 1150-1400 ℃ and strain rates of 0.001-1 s-1 using thermo-simulation machine. The constitutive equations of flow stress of V-5Cr-5Ti alloy at high temperature were established by utilizing hyperbolic sine function and introducing the strain factor with six polynomial fitting, then the accuracy of the constitutive equation was verified. The results show that during the hot compression deformation of V-5Cr-5Ti alloy, the characteristics of dynamic recrystallization and dynamic recovery are observed, respectively. The flow stress increases with increasing the strain rate, and decreases with increasing the temperature. The flow stress of V-5Cr-5Ti alloy predicted by the proposed models with 6th order polynomial fitting agrees well with the experimental value, the relative error is lower than 6.4% at the overwhelming majority (94%) cases of the deformation conditions, the average relative error is only 2.84%.
Key words: V-5Cr-5Ti; hot compression; constitutive equation; flow stress
