变形程度对铸态AZ31镁合金动态再结晶的影响

Effect of Deformation Degree on Dynamic Recrystallization of As-cast AZ31 Alloy

研究了铸态AZ31镁合金在温度为250～425℃、变形量为10%～40%、应变速率为0.01 s-1的条件下的热压缩时动态再结晶的变化规律,分析了流变应力与变形程度的关系。结果表明:铸态AZ31镁合金在应变速率为0.01 s-1的条件下进行热压缩变形,变形程度达到40%时,材料会发生断裂;当应变速率和变形温度一定时,流变应力随变形程度的增大不断增加,在达到峰值后逐渐降低,表现出明显的动态再结晶的特征;且随变形程度的增大,动态再结晶晶粒越来越多。

The dynamic recrystallization law of as-cast AZ31 alloy was investigated during hot compression deformation at 250～425 ℃ and various deformation degree（10%～40%） under the strain rates of 0.01 s-1.The relationship between flow stress and deformation degree was analyzed.The results show that the alloy breaks when the deformation degree approaches to 40%.With the increase of deformation degree,the flow stress of AZ31 alloy increases to the peak first and then decreases at constant deformation temperature and strain rate during hot compression deformation,which exhibits the characters of dynamic recrystallization.And the more the deformation degree increases,the more the grains of dynamic recrystallization.