真空粉末锻造成型FGH95合金的流变行为和组织演变

Flow behavior and microstructure evolution of FGH95 alloy formed by vacuum powder forging

利用Gleeble-3800热模拟试验机对真空粉末锻造成型FGH95合金的高温变形行为进行研究,在变形温度为1090~1170℃、应变速率为0.01~10 s^(−1)条件下进行热压缩实验,得到相应条件下流变应力-应变曲线,采用EBSD分析变形条件对真空粉末锻造成型FGH95合金微观组织演变的影响。在考虑温度、应变速率、应变量对合金流变行为的影响后,选择Arrhenius方程建立真空粉末锻造成型FGH95合金的本构模型,得出真空粉末锻造成型FGH95合金的材料参数,拟合出材料参数和应变量之间的关系并对得出的本构方程进行验证。结果表明:采用真空粉末锻造成形工艺制备的FGH95合金,在热变形过程中的流变应力随着温度的升高而减小,随着应变速率的升高而升高。变形后组织内的再结晶晶粒的尺寸随着温度的升高而减小,随着应变速率的降低而增大。经过计算得出变形激活能Q为685.7787 kJ·mol^(−1),真空粉末锻造成型FGH95合金流变应力的预测值和实验值的误差为6.33%,预测值和实验值吻合较好。

The high temperature deformation behavior of vacuum powder forging FGH95 alloy was studied by Gleeble-3800 thermal simulation testing machine.The hot compression test was carried out at the deformation temperature of 1090-1170℃and the strain rate of 0.01-10 s^(−1).The flow stress-strain curves under the corresponding conditions were obtained.The effects of deformation conditions on the microstructure evolution of vacuum powder forging FGH95 alloy were analyzed by EBSD.After considering the influence of temperature,strain rate and strain on the flow behavior of the alloy,the Arrhenius equation was selected to establish the constitutive model of vacuum powder forging FGH95 alloy,and the parameters of vacuum powder forging FGH95 alloy were obtained.The relationship between material parameters and strain was fitted and the obtained constitutive equation was verified.The results show that the flow stress of FGH95 alloy prepared by vacuum powder forging process decreases with the increase of temperature and increases with the increase of strain rate.The size of recrystallized grains in the deformed microstructure decreases with the increase of temperature and increases with the decrease of strain rate.The error between the predicted value and the experimental value of the flow stress of the vacuum powder forging FGH95 alloy is 6.33%,and the predicted value is in good agreement with the experimental value.