新型耐热合金TG700C热变形及动态再结晶行为

Hot deformation and dynamic recrystallization behavior of new heat resistant alloy TG700C

利用等温热压缩实验,研究了TG700C合金变形温度为1050~1250℃、应变速率为1~20 s-1、变形量为60%变形条件下的热变形及动态再结晶行为。对材料高应变速率下的变形热效应进行了温升修正,获得了该合金的流变曲线和热变形本构方程,热变形过程的表观激活能为Q=624.762 k J/mol。该合金经过温升修正后的流变曲线呈现稳态的流变应力,不同变形温度和应变速率下合金的流变应力存在差异。合金的动态再结晶形核方式为应变诱导晶界迁移形核,在高温低应变速率下,动态再结晶形核容易发生,再结晶的比例随着温度的升高和应变速率的降低而提高。

Thermal deformation and dynamic recrystallisation behavior of a TG700 C alloy were investigated by using isothermal compression at deformation temperature of 1050-1250 ℃,strain rate of 1-20 s-1and deformation amount of 60%.The temperature rise due to deformation heat effect under high strain rate was corrected,and the flow curves and the constitutive equation of the hot deformation of the alloy were established.The results indicate that the apparent activation energy of the alloy is 624.762 k J /mol during thermal deformation.Steady-state stress is exhibited in the flow curves of the alloy after the correction of the temperature increase by deformation heat effect.Different flow stress is observed for the alloy at different deformation temperatures and strain rates.The nucleation of the dynamic recrystallization of the alloy is by strain-induced grain boundary migration.Under high temperature and low strain rate,the dynamic recrystallization nucleation is easy to occur,the proportion of recrystallisation increases with the increasing temperature and decreasing strain rate.