(中國工程物理研究院，綿陽 621900)
摘 要: 采用熱物理模擬試驗機研究V-5Cr-5Ti在變形溫度為1150~1400 ℃和應變速率為0.001~1 s-1條件下的熱變形行為。采用雙曲正弦函數(shù)建立V-5Cr-5Ti合金高溫條件下的本構方程，通過六次多項式擬合的方法將應變引入到本構方程中。結果表明：V-5Cr-5Ti合金真應力-應變曲線表現(xiàn)出動態(tài)再結晶和動態(tài)回復兩種軟化機制。流變應力隨著應變速率的增加而增大，隨溫度的升高而減小。采用應變的六次多項式擬合得到的本構關系中，流變應力預測值與實驗值吻合較好，絕大多數(shù)(94%)情況下預測的誤差小于6.4%，平均相對誤差僅為2.84%。
關鍵字: V-5Cr-5Ti；熱壓縮；本構方程；流變應力
（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
