ZK60镁合金热压缩变形行为

Hot compression behavior of ZK60 magnesium alloy

为了研究ZK60镁合金的热变形行为,采用Gleebe-1500热模拟机在变形温度为423～673K、应变速率为0.001～10s-1条件下对合金进行的热压缩试验.分析合金流变应力与应变速率、变形温度之间的关系,通过引入Z参数建立合金流变应力本构方程,并观察合金变形过程中的显微组织演变.结果表明:变形温度低于473K且应变速率大于0.1s-1时试样发生宏观开裂;在变形温度较高和应变速率较低时,合金真应力-真应变曲线具有动态再结晶特征.随变形温度升高和应变速率的降低流变应力减小,热压缩后的组织中再结晶现象越明显;应变速率越高,再结晶晶粒越细小.

In order to investigate the hot deformation behavior of ZK60 magnesium alloy,compression tests of the alloy was performed on Gleebe-1500 thermal simulator at the temperature range of 423-673 K and the strain rate range of 0.001-10 s^-1.The relationship between flow stress and deformation temperature as well as strain rate were analyzed.The constitutive equation for ZK60 alloy was obtained by introducing Z parameter.Microstructure evolution of the alloy under different conditions was examined.The results show that the specimens cracked when the temperature was lower than 473 K and strain rate was higher than 0.1 s^-1.For higher deformation temperature and lower strain rate,the true stress-strain curves show a characteristc of dynamic recrystallization.With the increase of deformation temperature and the decrease of strain rate the flow stress decreases,also the dynamic recrystallization becomes easier.The higher strain rate,the smaller dynamic recrystallized grain size.