F316奥氏体不锈钢热变形行为与动态再结晶机制

Hot deformation behavior and dynamic recrystallization mechanism of F316 austenitic stainless steel

采用等温压缩实验,系统探究了F316奥氏体不锈钢在不同变形量(10%~50%)、变形温度(960~1120℃)和应变速率(0.1~1s^(-1))下的热变形行为与动态再结晶机制。研究表明,F316奥氏体不锈钢的动态再结晶以弓出形核为主要形核方式,应变速率增加和变形温度降低均会导致动态再结晶体积分数和再结晶晶粒尺寸逐渐减小。通过结合Arrhenius方程和Zener-Hollomon参数,成功建立了F316奥氏体不锈钢的流变应力本构方程,其变形激活能Q确定为491.54k J/mol,峰值应力随着变形温度的升高和应变速率的降低而显著增大。通过引入应变条件的影响,可对流变应力本构方程进一步优化,最终成功实现对F316不锈钢流变应力曲线的良好预测。

The hot deformation behavior and dynamic recrystallization(DRX)mechanisms of F316 austenitic stainless steel for nuclear-grade valves were systematically investigated by isothermal compression tests at different deformations(10%-50%),temperatures(960-1120℃),and strain rates(0.1-1s^(-1)).The results show that the bulge nucleation is the main nucleation mechanism of DRX.Both the increasing strain rate and decreasing deformation temperature led to the gradual decrease in the volume fraction and grain size of DRX.The constitutive equation of F316 austenitic stainless steel was established by combining with the Arrhenius equation and Zener-Hollomon parameters.The deformation activation energy was determined as 491.54kJ/mol,and the peak stress significantly increases with the increasing deformation temperature and the decreasing strain rate.The constitutive equation was further modified by considering the effects of strain,and a good prediction on the stressstrain curves of F316 stainless steel was successfully achieved.