高温合金Inconel 617B的热变形及动态再结晶行为

Thermal Deformation and Dynamic Recrystallization Behavior of Inconel 617B Superalloy

利用Gleeble-3500热模拟试验机研究了高温气冷堆热交换器用高温合金Inconel 617B在变形温度为950~1200℃,变形速率为0.01~5 s^-1条件下的热变形及动态再结晶行为。结合峰值应力构建了该合金的Arrhenius高温本构模型,用以描述热变形参数对变形抗力的影响规律,同时确定其热变形激活能为473.867 kJ/mol;基于Poliak-Jonas理论得到了Inconel 617B的临界动态再结晶条件,峰值应变与临界应变的线性拟合相关性达到97.8%,高温低速率下变形时临界应变值较小;建立了Avrami动态再结晶动力学模型,升高温度或减小变形速率可促进动态再结晶的发生,明确了原始奥氏体晶界是发生动态再结晶的主要形核点,且以非连续动态再结晶为主导。

The thermal deformation and dynamic recrystallization behavior of superalloy Inconel 617B used for heat exchangers in the high temperature gas-cooled reactor were studied by Gleeble-3500 simulator at a temperature of 950~1200℃and deformation rate of 0.01~5 s^-1.The Arrhenius constitutive model of the alloy was constructed based on the peak stress to describe the influencing law of thermal deformation parameters on the deformation resistance.Meanwhile,the activation energy of thermal deformation was determined to be 473.867 kJ/mol.Based on the Poliak-Jonas theory,the critical dynamic recrystallization condition of Inconel 617B was obtained,and the correlation of linear fitting between the peak strain and the critical strain reached 97.8%.The critical strain value was smaller at higher temperature and lower strain rate.The Avrami dynamic recrystallization kinetics model was established.It was clear that the occurrence of dynamic recrystallization could be promoted by increasing the temperature or decreasing the strain rate,and the original austenite grain boundaries were identified as the main nucleation sites for dynamic recrystallization,which was dominated by discontinuous dynamic recrystallization.