Aluminum alloy and preparation method thereof

The invention relates to the field of aluminum alloys, in particular to an aluminum alloy and a preparation method thereof. The aluminum alloy comprises an aluminum alloy matrix and a hard anodic oxide film located on the surface of the aluminum alloy matrix. The surface of the hard anodic oxide film is provided with micropores. Particles generated in the hard anodic oxidation process adhere to the inner walls of the micropores. The preparation method comprises the steps that, an aluminum alloy precursor needing to be treated is subjected to S1 alkali cleaning, S2 pickling, S3 acid etching, S4hard anodic oxidation, S5 hot water washing, S6 passivation and S7 sealing, thus the aluminum alloy is obtained, wherein an electrolyte used in hard anodic oxidation in the S4 comprises the components of phytic acid, oxalic acid, citric acid, boric acid and lactic acid. The prepared aluminum alloy is higher in corrosion resistance, higher in hardness and better in wear resistance, and can be applied to the fields of aero