Inconel 625合金高速热变形动态再结晶的临界条件

Critical Conditions of Dynamic Recrystallization during High Speed Hot Deformation of Inconel 625 Alloy

通过等温热压缩试验获得Inconel 625合金在变形温度为1000～1200℃,应变速率为1～80s-1条件下的真应力-应变曲线,利用加工硬化率,结合lnθ-ε曲线上的拐点判据及-(lnθ)/ε-ε曲线上的最小值,来研究Inconel 625合金动态再结晶的临界条件。结果表明,在该实验条件下,Inconel 625合金的lnθ-ε曲线均出现拐点特征,对应的-(lnθ)/ε-ε曲线出现最小值,该最小值处对应的应变即为临界应变;临界应变随应变速率的增大和变形温度的降低而增加,并且临界应变和峰值应变之间有一定的关系,即εc=0.69εp;动态再结晶时临界应变的预测模型可以表示为εc=4.41×10-4Z0.14261。

Hot compression tests of Inconel 625 alloy were conducted at deformation temperature range of 1 000- 200 ℃ and strain rates of 1-80 s^-1 to obtain true stress-true strain curves. The critical conditions of dynamic recrystallization for In- conel 625 alloy were studied by using the work hardening rate θ, combined with the inflection point criterion of in θ-ε curves and the minimum value of -δ（ln θ）/δε-ε curves. The results indicate that the in θ-ε curve of Inconel 625 alloy presents the inflection point, and a minimum value of -δ（In θ）/δε-ε curve appears, which means the critical strain εc. The critical strain increases with the strain rate increasing and the temperature decreasing. And there is a relationship between the critical strain εc and peak strain ε, i. e. εc = 0.69%. The predicting model of critical strain is described as εc = 4.41 × 10^-4 Z^0.142.61