轧制态7A60铝合金的热压缩显微组织及流变行为

Hot Compression Microstructure and Rheological Behavior of Rolled 7A60 Aluminum Alloy

对轧制态7A60铝合金在应变速率为0.1~0.01s-1、变形温度为250~350℃条件下热压缩的显微组织特征和流变应力进行实验研究。结果表明:随着应变速率的降低和温度的升高,材料的各向异性减弱,均匀性增强,晶粒发生明显粗化;在热变形的过程中该合金的主要软化机制为动态回复和动态再结晶,峰值应力随应变速率的增加而增大,随温度的升高而降低,在应变速率为0.01s-1时发生了明显的非连续动态再结晶行为。合金热变形的流变应力行为可用双曲正弦函数来表示,其热激活能为438.981kJ/mol。

The microstructral characteristics and flow behaviors of rolled 7A60 aluminum alloy experienced hot compression were investigated within a stress rate range of 0.1-0.01 s-1 and a temperature range of 250-350℃.The results confirmed the wea-kened anisotropy,the enhanced uniformity,and the obviously coarsened grain for the material with the decrease in strain rate and the increase in temperature.In the process of thermal deformation,the main softening mechanism is dynamic recovery and dynamic recrystallization.The peak stress increases with the increase of strain rate and decreases with the increase of temperature.And at the strain rate of 0.01 s-1,a significant discontinuous dynamic recrystallization behavior occurred.The rheological behavior of the alloy can be characterized by a hyperbolic sine function with a thermal activation energy of 438.981 kJ/mol.