Incoloy825高温合金热变形行为及动态再结晶模型

Hot deformation behavior and dynamic recrystallization model of Incoloy825 superalloy

采用Gleeble-3800热模拟试验机,对Incoloy825高温合金在应变为0.92、温度为950~1150℃和应变速率为0.001~1 s^(-1)条件下进行单道次压缩试验。依据真应力-真应变曲线建立了动态再结晶临界方程和动态再结晶动力学模型。结果表明,Incoloy825高温合金热变形对温度和应变速率较为敏感,真应力-真应变曲线整体满足硬化-软化-稳态的流变过程,动态再结晶是Incoloy 825高温合金材料的主要软化机制。在热变形过程中,动态再结晶临界应变随变形温度的升高和应变速率的降低呈减小趋势。对动态再结晶动力学模型进行分析发现,动态再结晶百分含量随变形温度的升高和应变速率的降低而增大,表明高变形温度和低应变速率对动态再结晶具有促进作用。

The single pass compression tests of Incoloy825 superalloy were carried out with Gleeble-3800 thermal simulator under the con-ditions of strain of 0.92,temperature of 950^(-1)150℃and strain rate of 0.001^(-1) s^(-1).Based on the true stress-true strain curves,the dy-namic recrystallization critical equation and dynamic recrystallization kinetic model were established.The results show that the hot deform-ation of Incoloy825 superalloy is sensitive to temperature and strain rate,the overall true stress-true strain curves satisfy the rheological process of hardening-softening-stabilization.The dynamic recrystallization is the main softening mechanism of Incoloy825 superalloy.Dur-ing hot deformation,the critical strain of dynamic recrystallization shows a decrease trend with the increase of deformation temperature and the decrease of strain rate.By analyzing the kinetic model of dynamic recrystallization,it is found that the percentage content of dynamic recrystallization increases with the increase of deformation temperature and the decrease of strain rate.It is shown that high deformation temperature and low strain rate can promote dynamic recrystallization.