AA7085铝合金热变形行为及加工图的研究

Hot deformation behavior and processing maps ofAA7085 aluminum alloy

摘要:

采用等温热压缩试验,研究了AA7085铝合金在变形温度为300～450℃、应变速率为0.01～10 s_-1的条件下的热变形行为和加工图。通过光学显微镜(OM),电子背散射(EBSD)和透射电子显微镜(TEM)表征了材料的微观组织。结果表明在不同应变条件下的加工图的叠加得到优化的工艺参数为：温度为390-450 ℃,应变速率低于 0.1s_-1. 微观组织表征表明了在安全区内,动态回复和动态再结晶是主要的变形机制。而在低温低速的条件下,在应变为0.5与0.7之间的第二相粒子的粗化可能是导致加工图从失稳区向安全区转换的原因。

Abstract:

The flow behavior and processing maps of homogenized AA7085 aluminum alloy were investigated by isothermal hot compression tests in the temperature range of 300-450?C and strain rate range of 0.01-10 s-1. Microstructure was characterized using Optical microscopy (OM), electron back-scattered diffraction (EBSD) and transmission electron microscopy (TEM). The results show that the superimposed processing maps at different strains exhibit the optimized deformation parameters with the temperature range of 390-450 ?C and strain rate of lower than 0.1s-1. Microstructure characterization reveals that dynamic recovery and recrystallization are the main deformation mechanisms in the safe regions.In the low temperature and low strain rate regions, the coarsening of particles between ε=0.5 and ε=0.7 may be responsible for the transformation from unstability to safe domain.