The invention discloses a high-strength Al-Zn-Mg-Cu aluminum
alloy and a preparation method thereof, and relate to the field of aluminum
alloy. The aluminum
alloy comprises, by weight, less than or equal to 0.5% of Si, less than or equal to 0.5% of Fe, 5.0%-7.0% of Zn, 2.0%-3.0% of Cu, 1.5%-3.0% of Mg, 0.15%-0.35% of Sc, 0.1%-0.2% of Zr, 0.1%-0.3% of Y, and the balance aluminum and non-impurities.The preparation method comprises the following steps of
smelting, die, refining and
impurity removal and gas removal, pouring, homogenizing heat treatment, three-dimensional
large deformation forgingpre-deformation, isothermal deformation
processing and heat treatment. A
casting mold adopts a
metal mold as an inner mold, the
casting mold is surrounded by a
cooling pipe, a sand mold is used as aspecial combination mold of an outer mold, and a high-quality and high-performance
casting is obtained; and the heat treatment comprisessolution treatment+gradient aging treatment. According to the prepared Al-Zn-Mg-Cu aluminum alloy, the strength reaches 650 MPa, the elongation is 10%-13%, the elongation is improved while the strength is improved, and the service life is prolonged; and the Al-Zn-Mg-Cu aluminum alloy has important value in the field of high-strength aluminum alloy.