Effect of silicon content on nucleation and growth of multiscale precipitates in Al–Mg–Si–Cu–Zn alloys for different aging paths

Controlling the precipitation evolution is an efficient strategy for optimization of those properties in Al–Mg–Si–Cu-(Zn) alloys. In this work, we have studied the precipitation evolution and mechanical behavior in Al–Mg–Si–Cu–Zn alloys with different aging routes and Si contents (0.55–1.08 wt%). The results reveal that multiscale precipitates can be formed under a certain aging route in Al–Mg–Si–Cu–Zn alloys, which can simultaneously improve the strength and elongation. Accordingly, the nucleation mechanism of multiscale precipitates in Al–Mg–Si–Cu–Zn alloys was put forward, which provides important guidance on designing the novel Al–Mg–Si–Cu–Zn alloys with high formability and rapid bake hardening response for automotive applications.