7150铝合金高温热压缩变形流变应力行为

在Gleeble-1500热模拟机上对7150铝合金进行高温热压缩实验,研究该合金在变形温度为300~450 ℃和应变速率为0.01～10 s~(-1) 条件下的流变应力行为.结果表明:流变应力在变形初期随着应变的增加而增大,出现峰值后逐渐趋于平稳;峰值应力随着温度的升高而减小,随着应变速率的增大而增大;可用包含Zener-Hollomon参数的Arrhenius双曲正弦关系来描述合金的热流变行为,其变形激活能为226.698 8 kJ/mol;随着温度的升高和应变速率的降低,合金中拉长的晶粒发生粗化,亚晶尺寸增大,再结晶晶粒在晶界交叉处出现并且晶粒数量逐渐增加;合金热压缩变形的主要软化机制由动态回复逐步转变为动态再结晶.

Flow stress behavior of 7150 aluminum alloy during hot compression deformation at elevated temperature

The flow stress behavior of 7150 aluminum alloy during hot compression deformation was studied by thermal simulation test at the deformation temperature of 300-450 ℃ and the strain rate of 0.01-10 s~(-1) on the Gleeble-1500 thermal-mechanical simulator. The results show that the flow stress increases with increasing strain and tends to be constant after a peak value. The peak stress increases with increasing strain rate, and decreases with increasing deformation temperature, which can be represented by a Zener-Hollomon parameter in the hyperbolic sine equation with the hot deformation activation energy of 226.6988 kJ/mol. With increasing temperature and decreasing strain rate, the elongated grains in the deformed samples are coarsened and the size of subgrain increases; the number of fine grain in grain boundary also increases, indicating that the main softening mechanism of the alloy during hot compression deformation transforms from dynamic recovery to dynamic recrystallization.