Inconel625高温合金J-C本构建模

J-C constitutive modeling of high temperature alloys Inconel625

为了研究Inconel625高温合金在较高温度和应变率变化范围内的热变形行为,采用CSS电子万能试验机和分离式霍普金森压杆试验装置对Inconel625高温合金进行准静态试验和霍普金森压杆试验,在温度为20~800℃、应变率为0.001~8000 s^(-1)范围内得到Inconel625高温合金的真实应力—应变曲线。结果表明:随着温度的升高,Inconel625高温合金的流动应力与屈服应力并不单一地随应变率增大而增大,同一温度条件下,随着应变率的增加,Inconel625高温合金的真实应力先增大后减小(分界线是应变率为6000 s^(-1));同一应变率条件下,Inconel625高温合金的真实应力随着温度的升高而减小。基于Johnson-Cook模型对其真实应力-应变曲线进行拟合分析,经过计算得到模型的预测值与实验值的相关性和绝对误差,并进一步改进Inconel625高温合金的Johnson-Cook本构模型,使模型能够更好地反映Inconel625高温合金在较高温度和应变率变化范围内的热变形规律。

In order to study the thermal deformation behavior of Inconel625 superalloy at high temperature and strain rate range, the quasi-static test and Hopkinson pressure bar test of Inconel625 superalloy were carried out by using CSS electronic universal testing machine and split type pressure bar test device. The true stress-strain curves of Inconel625 superalloy were obtained in the range of 20-800 ℃ centigrade and strain rate of 0.001-8000 s-（-1）. The experimental results show that the low stress and yield stress of Inconel625 superalloy do not increase with the increase of strain rate. Under the same temperature, the true stress of Inconel625 superalloy increases first and then decreases with the increase of strain rate（the dividing line is strain rate of 6000 s-（-1））. While under the same strain rate, the true stress of Inconel625 superalloy decreases with the increase of temperature. Based on the Johnson-Cook model, the true stress-strain curves are fitted and analyzed. The correlation coefficient and the absolute error between the predicted value and the experimental value are obtained by calculation. By improving the Johnson-Cook constitutive model of Inconel625 superalloy, the model can be used to characterize the themal deformation of Inconel625 superalloy at high temperature and strain rate range.