Abstract
The hot deformation behavior and workability of a Cu-bearing excess-Si 6xxx aluminum alloy (Al-Mg-Si) were systematically investigated via isothermal hot compression tests conducted at temperatures of 400-520°C and strain rates of 0.001-10 s−1. To eliminate experimental errors arising from interfacial friction and deformation-induced adiabatic heating, the raw true stress–strain data were corrected using friction and temperature correction models. Subsequently, a strain-compensated Arrhenius-type constitutive model was established to predict the flow stress as a function of deformation conditions. The deformation instabilities, dynamic softening mechanisms, and microstructural evolution were further analyzed through the combination of processing maps and electron-backscattered diffraction (EBSD) characterization. The results indicate that the developed constitutive model exhibits excellent predictive capability, with a correlation coefficient (R) of 0.996 and an average absolute relative error (AARE) of 2.50%. The apparent deformation activation energy was determined to be 187.144 kJ/mol. Microstructural observations reveal that dynamic recovery serves as the predominant softening mechanism, accompanied by limited dynamic recrystallization. Flow instability regions are primarily concentrated at high strain rates and tend to expand with increasing strain, while the optimal processing window is identified within the ranges of 470-520°C and 0.01-0.1 s−1. This work provides a theoretical foundation and experimental guidance for optimizing the hot working process of this Cu-bearing excess-Si 6xxx aluminum alloy.