High performance aluminum alloy for low pressure casting of minicar structural member and preparation method of high performance aluminum alloy

The invention relates to a high performance aluminum alloy for low pressure casting of a minicar structural member and a preparation method of the high performance aluminum alloy. The aluminum alloy for low pressure casing comprises the following components according to weight percentage: 9.5%-11.5% of Si, 0.45%-0.55% of Mn, 0.1%-0.4% of Mg, 0.05%-0.15% of Ti, 0.01%-0.02% of Sr, 0.01%-0.02% of B, less than 0.2 percent of Fe and the balance of Al. The raw materials are prepared in a resistance crucible oven, Ti, B and Sr are respectively added into the melted aluminum alloy in the form of intermediate alloy of Al-Ti5-B1, Al-Sr10, thus being prevented from being burned, aluminum alloy cast at low pressure under the casting condition that the casting temperature is 710 DEG C, the die temperature is 350 DEG C, the compressing speed is 0.04Mpa/s has casting-state strength of extension greater than 260MPa, and elongation greater than 9%. The aluminum alloy for low pressure casting has good mobility and is suitable for mold filling of large thin walled workpieces, and the casting-state casting has very high strength of extension and very good ductility, and can meet the property requirement of the minicar structural member.