Hot Deformation Behavior and Processing Map Considering Strengthening Effect for Al-10.0Zn-3.0Mg-2.8Cu Alloy

In this paper, a hot processing map that takes into the strengthening effect into account is optimized for the Al-10.0Zn-3.0Mg-2.8Cu alloy, mainly considering the crushing and dissolving behavior of the insoluble phase. The hot deformation experiments were performed by compression testing with strain rates ranging from 0.001 to 1 s^-1 and the temperature ranging from 380 to 460 °C. The hot processing map was established at the strain of 0.9. It exhibits that the appropriate hot processing region is located at the temperature from 431 to 456 °C and its strain rate is within 0.004-0.108 s^-1. The recrystallization mechanisms and insoluble phase evolution were demonstrated using the real-time EBSD-EDS detection technology for this alloy. It is verified that the work hardening can also be consumed by the coarse insoluble phase refinement with the strain rate increasing from 0.001 to 0.1 s^-1, besides the traditional recovery and recrystallization, but the effect of the insoluble phase crushing was weakened when strain rate increased over 0.1 s^-1. Better refinement of the insoluble phase was around strain rate in 0.1 s^-1, which exhibits adequate dissolving during the solid solution treatment, leading to excellent aging strengthen effects. Finally, the hot processing region was further optimized, so that the strain rate approaches 0.1 s^-1 instead of 0.004-0.108 s^-1. This will provide a theoretical support for the subsequent deformation of the Al-10.0Zn-3.0Mg-2.8Cu alloy and its' engineering application in aerospace, defense and military fields.