Abstract:The multi-pass hot compression test of 7055 aluminum alloy was performed at different temperatures and then the samples were heat treated by T6 heat treatment. The compressed samples were analyzed by OM and TEM. The results reveal that the average aspect ratio of the grains in the specimens compressed first decreases and then increases, the dislocation density decreases and subgrain diameter increases with the increase of deformation temperature. The effects of deformation temperature on the microstructure and mechanical properties of 7055 aluminum alloy after heat treatment were investigated by means of OM and mechanical property test. The results indicate that the deformation temperature significantly influences microstructure and mechanical property of 7055 aluminum alloy. The volume fraction of recrystallization grains presents a “fall-rise” pattern with the deformation temperature rising. The mechanical properties get better when the volume fraction of recrystallization grains decreases. Moreover, the volume fraction of recrystallization grain has a minimum value, appropriately 45%, and the sample exhibits the highest strength and elongation at the deformation temperature of 400 °C.

Key words: 7055 aluminum alloy; hot deformation temperature; hot compression; recrystallization