7085铝合金的高温压缩流变应力及软化行为

对均匀化炉冷态7085铝合金进行高温压缩实验,研究该合金在变形温度为350~450℃、变形速率为0.001~0.1 s 1和应变量为0~0.6条件下的流变应力及软化行为。结果表明:流变应力在变形初期随着应变的增加而迅速增大,出现峰值后逐渐软化进入稳态流变;随着变形温度的升高和应变速率的降低,峰值流变应力降低。采用包含Zener-Hollomon参数的Arrhenius双曲正弦关系描述合金的流变行为。分析和建立了应变量与本构方程参数(激活能、应力指数和结构因子)的关系,研究发现本构方程参数随应变量的增加而减少。合金的流变行为差异与动态回复再结晶和第二相粒子相关。

Flow stress and softening behavior of 7085 aluminum alloy during compression deformation at elevated temperature

The flow stress and softening behavior of furnace-cooled 7085 aluminum alloy were studied by isothermal compression in the condition of 350~450 ℃,strain rate range of 0.001~0.1 s 1and strain range of 0~0.6.The results show that the flow stress increases rapidly at the initial stage of deformation,and gradually softens into steady with increasing strain.The peak flow stress increases with increasing strain rate or decreasing deformation temperature.The flow stress of aluminum alloy 7085 during hot compression deformation can be expressed by hyperbolic sine equation including Arrhenius term.The relationship between strain and constitutive equation of parameters including activation energy,stress index and structure factor have been also analyzed and founded.It is shown that constitutive equation parameters decrease with increasing strain.The differences of flow stress can be explained based on dynamic recovery and dynamic recrystallization as well as second phase particles.