Flow behavior and microstructure evolution of 6A82 aluminium alloy with high copper content during hot compression deformation at elevated temperatures

The flow behavior and microstructure evolution of 6A82 aluminum alloy (Al-Mg-Si-Cu) with high copper content were studied on a Gleeble-1500 system by isothermal hot compression test in the temperature range from 320 to 530 °C and the strain rate range from 0.001 to 10 s−1. The results reveal that the flow stress of the alloy exhibits a continuous flow softening behavior at low temperatures of 320-390 °C, whereas it reaches steady state at high temperatures (≥460 °C), which are influenced greatly by the Zener-Hollomon parameter (Z) in the hyperbolic sine with the hot deformation activation energy of 325.12 kJ/mol. Microstructure characterizations show that prominent dynamic recrystallization and coarsening of dynamic precipitation may be responsible for the continuous flow softening behavior. Due to deformation heating at high strain rates (≥1 s−1), dynamic recrystallization is more prominent in the specimen deformed at 530 °C and 10 s−1 than in the specimen deformed at 460 °C and 0.1 s−1 even though they have very close ln Z values.