Effect of deformation pass on softening mechanism and microstructure of 7085 alloy

Thermal deformation plays a key role in improving the comprehensive performance of 7085 aluminium alloy. We simulated the thermal deformation with a Gleeble-3800 thermal simulator under various deformation passes. The results showed that the softening mechanism in every deformation pass is principally recovery, and recrystallisation is relatively low. The sample compression by the single pass deformation at 673 K has the maximum recrystallisation fraction of 27.4%. The recrystallisation fraction of the sample compressed by three passes at 673 K and holding time of 120s reaches 23.2% due to the activation of meta-dynamic recrystallisation. Meanwhile, static recovery is more sufficient and more regular sub-grains (73.8%) are observed. Additionally, multi-pass deformation process is adopted to decrease the texture intensity and grain anisotropy.