Inconel690合金高温高速热变形行为研究

High-Temperature High-Speed Hot Deformation Behavior of Inconel 690 Alloy

在Gleeble-3800热模拟试验机上,采用热压缩实验研究了不同变形条件下Inconel 690合金的高温变形行为与组织演变特点。实验中采用的变形温度为1000～1200℃,变形量为70%,变形速率为1.0～80.0 s-1。根据实验结果获得了该合金的应力-应变关系,并对峰值应力进行了线性回归,由此得到了该合金的高温材料常数,激活能Q=417.6 kJ.mol-1,α=0.003196 MPa-1,n=7.51,并最终得到了Inconel 690合金的高温变形本构方程。通过金相显微镜研究了合金动态再结晶规律与温度和应变速率的关系,结果表明:变形温度对Inconel 690合金组织的影响很大,随温度的升高,动态再结晶百分数逐渐增加,且伴随着晶粒的长大;而提高应变速率,变形的时间缩短,位错密度迅速增大,动态再结晶的驱动力增加,也可以使再结晶后的晶粒细化;当温度为1150℃左右,应变速率50～80 s-1时,能够得到均匀细晶组织。

The hot deformation characteristics of Inconel 690 alloy were investigated on the Gleeble-3800 thermal mechanical simulator.The testing temperatures were in the range of 1000~1200 ℃,the deformation degree was 70%,and the strain rates were from 1.0 to 80.0 s-1.The true stress-strain curves were obtained and the material constants,the activation energy Q of 417.6 kJ · mol-1,α of 0.003196 MPa-1,and n of 7.51,of high-temperature deformation of Inconel 690 alloy were obtained by the linear regression of peak stress.The constitutive equation of inconel 690 alloy was established finally.The relationship between the law of dynamic recrystallization and temperature,strain rate was studied by metallurgical microscope.The results showed that the microstructures of inconel 690 alloy were greatly affected by temperature,the percentage of dynamic recrystallization increased with the increasing of temperature,and accompanied by grain growth.The deformation time shortened while the strain rate enhanced.So the density of dislocation increased rapidly,and the driving force of dynamic recrystallization increased,thus the grain could also be refined.The uniform and fine microstructure could be acquired when the temperature was about 1150 ℃ and the strain rates were in the range of 50~80 s-1.