Abstract: This study focused on the effect of homogenization on precipitation behavior and recrystallization of Al-Zn-Mg-Cu alloy with twin roll casting (TRC). Furthermore， the influences of Al₃Zr precipitation and recrystallization levels on mechanical properties and intergranular corrosion (IGC) resistance were evaluated. The results showed that compared to the single-stage homogenization， the first stage of two-stage homogenization provides higher driving force and greater number of heterogeneous nucleation sites， which enhances the precipitation of Al₃Zr. In addition， different heating rates also affect the precipitation of Al₃Zr. The slow heating rate is beneficial to refine the size of Al₃Zr and increases the quantity density and volume fraction of Al₃Zr particles. During the solution treatment， variations of f/r ratio of Al₃Zr phase leads to different recrystallization resistance， so the proportion of recrystallization structure and the number of large angle grain boundaries of the samples homogenized after the T6 treatments decrease. These microstructures and the corresponding distributions of Al₃Zr slightly affected the mechanical properties， while they significantly improved the intergranular corrosion resistance.

Key words: two-stage homogenization; Al-Zn-Mg-Cu alloy; Al₃Zr precipitation; intergranular corrosion; twin-roll casting