C276合金高温拉伸变形的本构方程

采用电子材料试验机,研究C276高温合金在变形温度650℃～750℃、拉伸速度0.35mm/min～35mm/min条件下的高温拉伸变形行为,分析了变形温度、应变速率对C276合金变形行为的作用及影响规律。结果表明,变形温度和应变速率对合金流变应力有显著影响,流变应力随变形温度升高而降低,随应变速率提高而增大。在变形温度700℃、拉伸速度0.35mm/min和3.5mm/min时,曲线呈现出明显的稳态流变应力特征,合金变形机制以动态回复为主;在变形温度750℃时,随着应变量的增加,合金内发生动态再结晶。利用Zener-Hollomon参数建立了C276合金的变形抗力模型,求得变形激活能为327.66kJ/mol。为C276合金的热加工工艺制定,提供了理论和试验的依据。

Constitutive equation of hot tensile deformation for C276 superalloy

Hot-tensile behavior of C276 superalloy was studied within the deformation temperature range of 650℃~750℃ and the tensile speed range of 0.35mm/min~35mm/min by using universal testing machine.The results showed that deformation temperature and strain rate both had significant influences on the flow stress.The flow stress decreased with the increase of deformation temperature,while increased with the increase of strain rate.The deformation mechanism of C276 superalloy exhibited the dynamic recovery feature at the deformation temperature of 700℃ and the tensile speed of 0.35mm/min and 3.5mm/min.However,when the deformation temperature increased to 750℃,the dynamic recrystallization behavior occurred.Flow stress of C276 alloy during hot deformation process was characterized by Zener-Hollomon parameter including the Arrhenius term and the deformation activation energy was 327.66kJ/mol.Therefore,a scientific basis was provided for the reasonable choice of thermal parameters for C276 superalloy.