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使用Gleeble-1500热模拟机对ZK60镁合金进行应变速率0.001~1s-1,温度523~673K条件下的热压缩实验。分析ZK60镁合金热压缩过程中的真实应力-应变曲线,分别总结变形温度和变形速率对流变过程中峰值应力的影响,建立描述ZK60镁合金高温压缩变形过程中的流变应力本构模型。将该方程导入有限元分析软件中,对ZK60镁合金热压缩过程进行数值模拟,分析热压缩过程中工件内部的等效应力和等效应变场的变化。研究表明:在该实验条件下的ZK60镁合金热压缩的真实应力-应变曲线有明显的动态再结晶特征,在高温下或者低应变速率下,流变应力曲线的峰值应力变小;模拟所得到的应力-应变曲线与热压缩的测应力-应变曲线基本吻合,表明所求ZK60高温流变本构模型可以为ZK60镁合金热加工提供参考依据。
The thermal compression experiment of ZK60 magnesium alloy at strain rate of 0.001 ~ 1s-1 and temperature of 523 ~ 673K was carried out by using Gleeble-1500 thermal simulator. The effect of deformation temperature and deformation rate on the peak stress in rheological process was summarized respectively. The constitutive model describing the flow stress in ZK60 magnesium alloy during high temperature compression deformation was established. The equation was introduced into the finite element analysis software to simulate the thermal compression process of ZK60 magnesium alloy and analyze the changes of equivalent stress and equivalent strain field in the workpiece during hot compression. The results show that the true stress-strain curve of ZK60 magnesium alloy has obvious dynamic recrystallization under the experimental conditions. The peak stress of the flow stress curve becomes smaller under high temperature or low strain rate. The stress-strain curve is basically consistent with the measured stress-strain curve of hot compression, indicating that the proposed ZK60 high temperature rheological constitutive model can provide a reference for the thermal processing of ZK60 magnesium alloy.