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采用高温拉伸试验研究了GH3230合金在温度1144~1273 K、应变速率1×10-3~1×10-1s-1条件下的热变形行为。计算了变形激活能,并采用Zener-Hollomon参数法构建合金的高温变形的本构关系。结果表明:温度和应变速率对GH3230合金的高温力学性能有显著影响,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。GH3230合金的高温流变行为可用Zener-Hollomon参数的双曲正弦函数来描述,热变形材料常数为:A=5.179×1016s-1,a=0.0088,n=3.9893,并计算出合金的平均变形激活能Q=455.203 k J·mol-1,且变形激活能更容易受到应变速率的影响。扫描电镜(SEM)断口分析表明GH3230合金在高温下(1144~1273 K)应变率范围为1×10-3~1×10-1s-1时的拉伸断裂都是由损伤引起的韧性断裂,且温度对断口形貌影响不大,但应变速率增大会使韧窝尺寸和深浅变小。
The hot deformation behavior of GH3230 alloy at temperature of 1144 ~ 1273 K and strain rate of 1 × 10-3 ~ 1 × 10-1 s-1 was studied by high temperature tensile test. The deformation activation energy was calculated and the constitutive relation of high temperature deformation of alloy was established by Zener-Hollomon parameter method. The results show that the temperature and strain rate have a significant effect on the mechanical properties of GH3230 alloy. The flow stress decreases with the increase of deformation temperature and increases with the increase of strain rate. The high temperature rheological behavior of GH3230 alloy can be described by the hyperbolic sine function of Zener-Hollomon parameter. The thermal deformation material constants are: A = 5.179 × 1016s-1, a = 0.0088, n = 3.9893, and the average deformation activation Q = 455.203 kJ · mol-1, and the deformation activation energy is more easily affected by the strain rate. Scanning electron microscopy (SEM) fracture analysis shows that tensile fracture of GH3230 alloy is caused by damage at high temperature (1144 ~ 1273 K) strain rate range of 1 × 10-3 ~ 1 × 10-1s-1, And the effect of temperature on fracture morphology is not significant, but the increase of strain rate will make dimple size and depth smaller.