Mg-3Zn-1Zr合金热变形行为及其本构模型

Thermal deformation behavior of Mg-3Zn-1Zr alloy and its constitutive model

采用Gleeble 3800热模拟机测试了Mg-3Zn-1Zr合金在温度为250～350℃、应变速率为0. 01～1 s-1条件下的多组热模拟压缩变形行为。结果表明:合金在热压缩时表现出明显的动态再结晶特征,随应变的增加流动应力先快速增加,然后经过一个缓慢的增加后达到峰值,最后极缓慢的下降并保持稳定。合金热变形时的流动应力对变形温度和变形速率非常敏感,随变形速率的增加而增大,随变形温度的升高而降低。利用热模拟压缩实验数据,基于Arrhenius方程和Zener-Hollomon参数,运用多元回归分析方法建立了Mg-3Zn-1Zr合金在高温变形过程中的流变应力本构模型。

The simulation hot deformation behavior of Mg-3Zn-1Zr alloy was tested by Gleeble 3800 machine at the temperature range of 250~350℃,strain rates between 0.01s-1~1s-1 of the samples.The results show that the alloy exhibits obvious dynamic recrystallization characteristics during the thermal compression.With the increase of strain,the flow stress first increased rapidly,then reached a peak after a slow increase,and finally decreased very slowly and remained stable.The flow stress of the alloy was very sensitive to strain rate and deformation temperature,and increased as increasing of the strain rate and decreased with deformation temperature increasing.The flow stress model of the Mg-3Zn-1Zr alloy during high temperature deformation was established based on the Arrhenius equations and Zener-Hollomon parameter by using thermal simulation compression experimental data.