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采用G leeb le-3500热模拟试验机进行高温等温压缩实验,研究了GH690合金在变形温度为950~1250℃、应变速率为0.001~10 s-1条件下的热变形行为,采用金相显微镜对GH690合金热模拟试样的纵截面变形组织进行观察。结果表明:应变速率和变形温度对合金的流变应力与变形组织有显著影响。流变应力随变形温度的升高而降低,随着应变速率的增加而升高,说明该合金属于正应变速率敏感的材料;动态再结晶晶粒尺寸随应变速率的增加而减小,随变形温度的增大而增大。采用Zener-Hollomon参数的双曲正弦函数能较好地描述GH690合金高温变形时的流变行为,得到峰值应力表达式,GH690合金的热变形激活能Q为370.4 k.Jmol-1。
The high temperature isothermal compression experiments were carried out on a G leeb le-3500 thermal simulation machine. The thermal deformation behavior of the GH690 alloy was investigated at a deformation temperature of 950-1250 ℃ and a strain rate of 0.001-10 s-1. Metallographic microscope GH690 alloy thermal simulation of the longitudinal section of the sample deformation was observed. The results show that strain rate and deformation temperature have significant influence on the flow stress and deformation of the alloy. The flow stress decreases with the increase of the deformation temperature and increases with the increase of the strain rate, indicating that the alloy belongs to the positive strain rate sensitive material. The dynamic recrystallization grain size decreases with the increase of the strain rate, Increase the temperature increases. The hyperbolic sine function of Zener-Hollomon parameter can well describe the rheological behavior of GH690 alloy under high temperature deformation and obtain the peak stress expression. The heat deformation activation energy Q of GH690 alloy is 370.4 kJJmol-1.