Aluminium alloy material for car wheel hubs and preparation method thereof

The invention provides an aluminium alloy material for car wheel hubs. The aluminium alloy material comprises the following chemical elements by mass percent: 7.2-7.5% of zinc, 3.6-4.1% of magnesium, 0.2-0.4% of copper, 0.9-1.1% of zirconium, 0.1-0.2% of titanium, 0.4-0.5% of chromium, 0.02-0.05% of scandium, 0.1-0.3% of Be, 0.03-0.05% of La and the balance of aluminium. The aluminium alloy material has the beneficial effects that the ratio of the elements of the aluminium alloy is reasonable; by reasonably controlling the treatment temperature after casting and putting alloy elements in batches, the alloy is uniform in crystallization and has high strength, high impact toughness and high corrosion resistance, and the production cost is reduced while the mechanical performances of the aluminium alloy wheel hubs are ensured; part of waste aluminium is used as the raw material, so that the alloy has more stable and uniform quality; a refining agent is used for casting production, can reduce the porosity in castings by 1-2 degrees, has about two-grade oxide inclusions, and has high yield.