Regulate and Control Grain Structure Characteristics and Mechanical Properties Control of Al-Zn-Mg-Cu Alloy

Abstract

Grain characteristics are one of the most important factors in determining alloy properties. Thermal deformation and solution treatment experiments were used to investigate the evolution of grain features and mechanical properties of Al-9.39 Zn-1.92 Mg-1.98 Cu alloy. The results reveal that when the deformation temperature rises, the recrystallized grain size, recrystallization fraction, and sub-grain size for the alloy's final microstructure gradually increase. The recrystallized grain size and fraction increase as the solution temperature rises, although the sub-grain size of the final microstructure of the corresponding alloy changes slightly. Fitting is used to deriving the function of recrystallization size, recrystallization fraction, and sub-grain size as a function of deformation temperature. The tensile properties of the alloy at T6 state are the best after deformation at 400°C and solution treatment at 470°C. The brittle fracture mode is shown in recrystallized grains, whereas the toughness fracture mode is shown in sub-grains.