中文摘要：

采用Gleeble-3500热模拟试验机研究了Hastelloy C-276镍基合金在不同变形条件下的热压缩流变应力曲线,热变形过程中发生了动态再结晶行为。利用加工硬化率-应力关系曲线确定了动态再结晶临界条件,采用Johnson-Mehl-Avrami（JMA）方程计算再结晶体积分数实验值,建立了C-276合金动态再结晶体积分数和晶粒尺寸预测模型。结果表明：C-276合金动态再结晶体积分数随着应变量的增加,呈现典型的＂S型＂曲线;获得临界应变条件表达式：lnε_c=0.144lnZ-7.173;动态再结晶体积分数表达式X_（drx）=1-exp{-1.4034[（ε-ε_c）/ε_（0.5）]~（2.58384）},预测值和实验值的平均误差为2.16%;晶粒长大表达式d_（drx）=6.58×10~3Z~（-0.168）,预测值和实验值的平均误差为6.63%。

英文摘要：

The flow stress curve of Nickel base alloy Hastelloy C-276 during hot deformation was investigated by compression tests at varying temperatures and strain rates up to a true strain of 0.7 on Gleeble 3500 simulator.Dynamic recrystallization（DRX） occurred during hot deformation.The recrystallization critical conditions were determined by relationships between work hardening rate and stress curve.Experimental values of recrystallization volume fraction were calculated by Johnson-Mehl-Avrami（JMA） equation,and the dynamic recrystallization volume fraction model as well as the grain growth forecast model of Hastelloy C-276 alloy was established.The results show that the increment of recrystallization volume fraction is the typical ＂S＂ type curve with the increase of strain.The equation of critical strain conditions is established as lnε_c=0.144lnZ-7.173.The equation of recrystallization volume fraction is X_（drx）=1-exp{-1.4034[（ε-ε_c）/ε_（0.5）]~（2.58384）},and the average error of the predicted values and experimental values is 2.16%.The grain growth equation is d_（drx）=6.58×10~3Z~（-0.168）,and the average error is 6.63%.