The invention discloses a heat treatment-free die-
casting aluminum
alloy for a structural part. The heat treatment-free die-
casting aluminum
alloy comprises the following components in percentage by
mass: 7.5%-11.5% of Si, less than or equal to 0.2% of Fe, 0.6%-1.2% of Mg, 0.05%-0.8% of Mn, 0.05%-0.4% of Cr, 0.03%-0.3% of Ta, 0.03%-0.3% of Nb, 0.03%-0.3% of Ni, 0.01%-0.12% of Ti, 0.03%-0.6% of Y, 0.03%-0.6% of Ce, 0.03%-0.6% of Er, 0.005%-0.05% of Sr and the balance of aluminum. The preparation method comprises the following steps: mixing and
smelting an aluminum
ingot,
metal silicon, an aluminum-
manganese intermediate
alloy, an aluminum-
chromium intermediate alloy, an aluminum-
tantalum intermediate alloy, an aluminum-
niobium intermediate alloy, an aluminum-
nickel intermediate alloy, an aluminum-
titanium intermediate alloy, an aluminum-
yttrium intermediate alloy, an aluminum-
cerium intermediate alloy and an aluminum-
erbium intermediate alloy to obtain a melt I; adding a
magnesium ingot into the melt I,
smelting, introducing
argon, refining to obtain molten aluminum, and
casting to obtain an aluminum alloy
ingot. The method is suitable for high-
pressure casting forming to prepare force-bearing structural parts with complex shapes, can have good mechanical properties without heat treatment, and can be used for production of various parts required by
new energy automobiles.