【摘要】 采用Gleeble-1500热模拟机对ZK60镁合金在温度为200~400℃、应变速率为0.001~10 s-1、最大变形量为60%的条件下进行恒应变速率高温压缩实验,研究高温变形过程中合金的动态再结晶行为;采用EM模型描述合金的动态回复曲线,以此为基础,得出ZK60合金热压缩过程中的动态再结晶动力学Avrami方程。利用有限元模拟合金热压缩过程中的动态再结晶。结果表明:ZK60合金热压缩过程中由于存在动态再结晶的软化作用,流变应力达到峰值后逐渐减小,并最终达到稳态;随着变形量的增加和变形温度的升高,动态再结晶体积分数增加,合金变形更加均匀;随着应变速率的增加,动态再结晶分数有所减小,且变形也更不均匀。更多还原

【Abstract】 The kinetics of dynamic recrystallization of ZK60 magnesium alloy was investigated by compression tests at temperature of 200-400 ℃ and strain rate of 0.001-10 s-1.The flow stress curves considering only dynamic recovery was described by EM model.Based on EM model,the kinetics of dynamic recrystallization of ZK60 alloy was modeled by an Avrami-type equation.The finite element simulations were utilized to simulate the recrystallization process of ZK60 alloy during hot compression.The results show that,due to the effect of dynamic recovery,the flow stress increases to a peak value and subsequently decreases to steady state.Both the volume fraction of dynamic recrystallization and the deformation homogeneity increase with the increase of the plastic strain and deformation temperature,while decrease with the increase of strain rate.更多还原