Investigation on Compressive Formability and Microstructure Evolution of 6082-T6 Aluminum Alloy

The 6xxx aluminum alloy is the first choice for automotive lightweight forgings due to its excellent performance, high strength and low weight. The production time of current aluminum alloy forging generally exceeds 10 h. To reduce the production time of traditional aluminum alloy forgings, 6082-T6 aluminum alloy is used in the forming process. The effects of different heating temperatures (200 degrees C, 300 degrees C, and 400 degrees C) and deformation degrees (30%, 50%, and 70%) on the deformability and properties of 6082-T6 billets have been investigated. The results show that when the heating temperature is higher than 300 degrees C, the compressive deformation resistance obviously decreases with increasing strength. With compression at 200 degrees C and 70% deformation with short heating time, the strength of the sample is close to the T6 (solution treatment and artificial aging) state. A large number of dislocations and subgrains were introduced due to the compression deformation, and their amounts decreased as the heating temperature increased. The size of the precipitated phase beta '' slightly grows under a heating temperature of 200 degrees C. However, when the heating temperature is higher than 300 degrees C, the precipitated phase gradually changes from beta '', which is optimal for the strengthening effect, to beta ' and beta, which offer weaker strengthening. Therefore, under a lower heating temperature of 200 degrees C for 5 min, a large number of dislocations are introduced with the beta '' precipitated phase, leading to higher strength with less heat treatment time.