Heat-treatment-free die-cast aluminum alloy and preparation method and application thereof

A method for preparing a heat-treatment-free die-cast aluminum alloy, comprising:

• melting an aluminum ingot in a smelting furnace, and adding an industrial silicon, a Zn material, a Cu material and a Mn material for a first smelting to obtain a first melt;
• subjecting the first melt to a refining treatment and a slagging-off treatment to obtain a second melt;
• adding a Ti material, a Sr material, a rare earth material comprising at least one of a Sm material or an Y material, and a Mg material to the second melt for a second smelting to obtain a third melt;
• degassing the third melt to obtain a fourth melt;
• and
• high-pressure die casting the fourth melt to obtain the heat-treatment-free die-cast aluminum alloy.

An automobile body structural member, comprising a heat-treatment-free die-cast aluminum alloy comprising:

• 10.0 to 12.0 wt % of Si,
• 0.9 to 1.5 wt % of Mg,
• 2.5 to 3.5 wt % of Cu,
• 0.4 to 0.8 wt % of Mn,
• 0.9 to 1.5 wt % of Zn,
• 0.1 to 0.2 wt % of Ti,
• 0.03 to 0.06 wt % of Sr,
• 0.18 wt % or less of Fe,
• 0.15 wt % or less of a rare earth element,
• 0.1 wt % or less of an impurity element, and
• a balance of Al,
• based on a total weight of the die-cast aluminum alloy,
• wherein the rare earth element comprises at least one of Sm or Y.