High-strength al—cu—mg—mn aluminum alloy and preparation method therefor

Abstract

A high-strength Al—Cu—Mg—Mn aluminum alloy and a preparation method therefor is provided. The alloy includes the following components in percentage by weight: Si: ≤0.5%, Fe: ≤0.5%, Cu: 4.5-6.3%, Mg: 0.6-1.2%, Mn: 0.6-1.5%, Sc: 0.15-0.35%, Zr: 0.1-0.2%, and Y: 0.1-0.3%, the balance being aluminum and non-removable impurities. The preparation method includes: smelting, refining, impurity removing and degassing, pouring, homogenizing heat treatment, three-dimensional large deformation forging pre-deformation, isothermal deformation processing, and heat treatment. A casting mold used is a special combined mold having a metal mold as an inner mold, a surrounding cooling pipe, and a sand mold as an outer mold, and is used to prepare and obtain high-quality, high-performance castings. The heat treatment is solid solution treatment plus gradient aging treatment. The Al—Cu—Mg—Mn aluminum alloy has a tensile strength higher than 520 MPa and an elongation of 12-16%, that is, an increased elongation rate and improved strength.