半固态7050铝合金热压缩变形行为

在Gleeble-3500热模拟机上对半固态7050铝合金进行了高温热压缩试验,研究了该合金在变形温度为420～465℃、应变速率为0.001～0.100s-1条件下的流变应力行为以及变形过程中的显微组织。结果表明,流变应力在变形初期随着应变的增大迅速增大,出现峰值应力后逐渐平稳,流变应力随着应变速率的增大而增大,随着变形温度的升高而下降;流变应力可以用双曲线正弦形式的关系来描述,通过线性拟合计算出该材料的形变激活能等参数,获得流变应力的本构方程。随着变形温度升高和应变速率降低,合金中拉长的晶粒变大,合金热压缩变形的主要软化机制为动态再结晶。

Hot Compression Behavior of Semi-solid 7050 Aluminum Alloy

The flow stress behavior and microstructure of semi-solid 7050 aluminum alloy during hot compression deformation process were investigated on the Gleeble-3500 thermal-mechanical simulator at the deformation temperature of 420~465 ℃ and strain rate of 0.001~0.1 s-1.The results show that the flow stress is increased sharply to reach the peak value with increasing in strain at the initial stage,and then tends to be constant,and it is increased with the strain rate increase while it is decreased with rising the deformation temperature.The flow stress can be described by a constitutive equation in hyperbolic sine function.The deformation activation energy is evaluated by linear regression analysis to construct the constitutive equation on flow stress of the alloy during hot compression.With increasing in temperature and decreasing in strain rate,the elongated grains in the deformed alloy is grown.The main softening mechanism of the deformed alloy during hot compression deformation exhibits dynamic recystallization.