Hastelloy C-276镍基合金的热压缩变形行为

Hot Compressive Deformation Behaviors of Nickel Base Alloy Hastelloy C-276

采用Gleeble-3500热模拟试验机研究了Hastelloy C-276镍基合金在0.01～10 s-1、1000～1250℃、应变量0.7条件下的高温恒温压缩变形行为,对热压缩后的组织进行了金相显微分析。结果表明:C-276合金热变形流变应力随着应变速率的增大和变形温度的降低而增大。热变形过程中发生了动态再结晶,当温度T≥1200℃时,发生了完全动态再结晶,T<1200℃时,发生部分动态再结晶。热变形流变应力可用Zener-Hollomon参数来描述,根据修正后的流变应力曲线建立了Hastelloy C-276合金峰值应力下的高温变形本构方程,热变形材料常数为:激活能Q=446.51 kJ·mol-1,α=0.0037346,n=4.42851,A=1.11×1016。

The hot deformation behavior of nickel base alloy Hastelloy C-276 was investigated by compression test under isothermal hot working conditions of varying temperature （between 1000 and 1250 ℃ ） and strain rates（between 0.01 and 10 s ^-1 ） up to a true strain of 0.7 on Gleeble 3500 simulator. The deformed microstructures of vertical sections were observed by using optical microscope. The results showed that the flow stress of C-276 decreased with the increase of strain rate and with the increase of deformation tempera- ture. Dynamic recrystallization（DRX） occurred during hot deformation; there was a complete dynamic recrystallization when tempera- ture was not less than 1200 ℃, and part of dynamic recrystallization when temperature was less than 1200 ℃. The flow stress of the al- loy during thermal deformation can be described by a Zener-Hollomon parameter to described. The constitutive equation under peak stress was established based on the corrected flow stress. The material constants of thermal deformation were as follows ： activation ener- gy Q of 446.51 kJ.mol-1, α of 0.0037346, n of 4.42851, and A of 1.11 × 1016.