Effect of Mg on microstructure and properties of Al-8.95Zn-(1.9 ∼ 2.6)Mg-1.18Cu-0.44Zr rolled aluminum alloy

Effect of Mg on microstructure and properties of 7000 high strength rolled aluminum alloy was studied by XRD and EBSD analysis, hardness and electric conductivity test, tensile test and intergranular corrosion experiments. The results show that for Al-8.95Zn-(1.9 ~ 2.6)Mg-1.18Cu-0.44Zr 7000 series aluminum alloy, it has excellent comprehensive performance in T76 state with high tensile strength of 585 ~ 645 MPa and elongation of 10.2 ~ 15.4%, and the resistance to intergranular corrosion is excellent(≤72 μm). When the content of Mg is 2.21%, the aluminum alloy has the highest degree of recrystallization, and the strength and elongation rates of aluminum alloy with T6 and T76 aging state can reach 651.7 MPa and 10.7%, 645.6 MPa and 15.4%, respectively, but the resistance to intergranular corrosion is relatively poor. At the same time, the resistance to intergranular corrosion of the alloy decreases as the degree of recrystallization increases.