中文摘要：

在Gleeble-1500型热模拟压缩机上研究7A09铝合金在温度为633~733 K、应变速率为0.01~10.0 s-1、最大变形程度为60%条件下的高温流动行为;基于7A09铝合金高温压缩时的流动应力特征,建立反映应变影响的7A09铝合金流动应力模型。结果表明：随着变形温度的升高和应变速率的降低,合金的流动应力显著降低;当应变超过一定值后,随着应变的增加,高、低应变速率下合金的流动应力变化趋势不同;建立的流动应力模型的计算值与实验值之间的最大误差为7.77%,平均误差为2.69%;与不考虑应变影响的流动应力模型相比,该模型的拟合精度高,能较好地描述7A09铝合金高温变形过程中的流动行为,为铝合金高温变形过程的数值模拟奠定了较好的基础。

英文摘要：

The flow behavior of isothermally compressed 7A09 aluminum alloy in the deformation temperature range from 633 to 733 K,the strain rate range from 0.01 to 10.0 s-1 and the maximum deformation of 60% was investigated on a Gleeble-1500 isothermal compressor.Meanwhile,a flow stress model considering the contribution of the strain was established in the isothermal compression of 7A09 aluminum alloy.The results show that the flow stress of 7A09 aluminum alloy significantly decreases with the increase of the deformation temperature and the decrease of strain rate.After a critical value of strain,the flow stress changes differently with the increase of the strain at higher and lower strain rates.The maximum and the average differences between the calculated flow stress by the flow stress model and the experimental ones are 7.77% and 2.69%,respectively.The comparison between the present flow stress model and that without considering the strain shows that the present flow stress model has higher precision and can efficiently predict the flow behavior in the isothermal compression of 7A09 aluminum alloy.The present flow stress model is also beneficial to the FEM simulation of thermal deformation for 7A09 aluminum alloy.