Hastelloy C-276合金热变形动态再结晶模型研究

Research on Dynamic Recrystallization Behavior of Hastelloy C-276 Alloy during Hot Deformation

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： ；动态再结晶体积分数表达式 ，预测值和实验值的平均误差为2.16 %；晶粒长大表达式 ，预测值和实验值的平均误差为6.63 %。

Abstract:

The flow stress curve of Nickel base Alloy Hastelloy C-276 during hot deformation was investigated by compression test under varying temperature 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. Adopt Johnson-Mehl-Avrami(JMA) equation to calculate recrystallization volume fraction experimental value, established the dynamic recrystallization volume fraction model and grain growth forecast model of Hastelloy C-276 alloy. The results show that the increasement of recrystallization volume fraction presents the typical "S" type curve with the increase of strain. The equation of critical strain conditions was established ．The equation of recrystallization volume fraction is ，and the average error of the predicted values and experimental values was 2.16%. The grain growth equation is , the average error was 6.63%.