25CrMo4钢热压缩变形行为及流变应力本构方程

Thermal compressive deformation behavior and flow stress constitutive equation of 25CrMo4 steel

通过Gleeble-1500型热/力试验机对25CrMo4钢进行了热压缩实验,研究了25CrMo4钢在应变速率为0.1、1和10 s^-1,变形温度为1050、1100和1150℃条件下的热压缩变形行为。结果表明,该材料软化机制以动态再结晶为主。采用Arrhenius双曲正弦函数建立了25CrMo4钢峰值应力本构方程,确定了25CrMo4钢的变形激活能为441 kJ·mol^-1。通过将峰值应力本构方程中的材料常数替换为应变的多项式函数,建立了综合应变速率、变形温度以及应变量的流变应力本构方程。该方程计算得出的数据与实验数据吻合较好,说明其可精确描述25CrMo4钢的热压缩变形行为。

Thermal compression test of 25CrMo4 steel was conducted by Gleeble-1500 thermal-mechanical testing machine,the thermal compressive deformation behavior of 25CrMo4 steel was investigated at the strain rate of 0. 1,1 and 10 s^-1 and the deformation temperature of 1050,1100 and 1150 ℃. The results show that main softening mechanism of this material is dynamic recrystallization. The peak stress constitutive equation was established based on Arrhenius hyperbolic sine function. The deformation activation energy of 25CrMo4 steel is 441 kJ·mol^-1. By replacing the material constant of the peak stress constitutive equation with a polynomial function of strain,a flow stress constitutive equation coupling strain rate,deformation temperature and strain was established. The calculated values are in good agreement with the experimental results,which indicates that the equation can accurately describe the thermal compressive deformation behavior of 25CrMo4 steel.