压铸A356铝合金的热变形行为

Hot Deformation Behavior of Water-cooled Die-casting A356 Aluminum Alloy

通过水冷压铸制备A356铝合金,利用热压缩试验对合金进行了热变形行为研究。分析了该合金的应力-应变曲线,建立了本构方程并绘制了热加工图。结果表明,该合金的流变应力随着应变速率的增大和变形温度的降低而增加,合金热变形过程中的软化机制主要为动态回复,同时计算得到其平均热变形激活能为238.6kJ·mol^(-1)。通过热加工图和热压缩后合金的微观组织分析,发现在温度为330~380℃和应变速率为5~10s^(-1)范围内该合金具有良好的热加工性能。

A356 aluminum alloy was prepared by water-cooled die casting,and the hot deformation behavior of the alloy was analyzed by hot compression experiment.The stress-strain curve of the alloy was analyzed,and the constitutive equation was established,in addition,the hot working diagram was drawn.The results reveal that the flow stress of the alloy is increased with the increase of strain rate and the decrease of deformation temperature.It is also found that the softening mechanism of the alloy during thermal deformation is characterized by mainly dynamic recovery.At the same time,the average thermal deformation activation energy Q is calculated to be 238.6 kJ·mol^(-1).Through the hot working diagram and microstructure analysis of the alloy after hot compression,it is found that the alloy presents the satisfied hot workability at 330~380℃and 5~10 s^(-1).