Heat-treatment-free high-toughness die-casting aluminum alloy and preparation method thereof

Abstract

The invention discloses a heat-treatment-free high-toughness die-casting aluminum alloy and a preparation method thereof. The alloy comprises the following components in percentage by weight: 7.5 to 9.5 percent of Si, 0 to 1.5 percent of Ni, 0.4 to 0.8 percent of Mn, 0 to 0.4 percent of Mg, 0.08 to 0.3 percent of Cr, 0.01 to 0.15 percent of Zr, 0.03 to 0.1 percent of Ti, 0.005 to 0.025 percent of Sr and the balance of aluminum and inevitable impurity elements. The die-casting aluminum alloy is good in thermal stability, the mechanical property change does not exceed 10% after the die-casting aluminum alloy is kept at the temperature not higher than 150 DEG C for 1000 h, the die-casting state yield strength is larger than 120 MPa, the elongation is larger than 14%, the performance requirement of a car body die-casting structural part can be met without subsequent heat treatment, and the die-casting aluminum alloy is suitable for large-scale production. And the percent of pass of thin-wall die-casting structural part products can be greatly increased, and the use cost of automobile parts is reduced.

Description

technical field [0001] The invention relates to the technical field of metal materials, in particular to a heat-free die-casting aluminum alloy with excellent thermal stability and high strength and toughness and a preparation method thereof. Background technique [0002] In recent years, with the implementation of the lightweight development strategy and the rapid development of die-casting equipment and process technology, the use of high-vacuum die-casting for automotive stress-bearing structural parts has become an important way for new energy vehicles to achieve lightweight. At present, aluminum alloy die-casting structural parts generally use AlSiMnMg alloys with heat treatment to achieve the strengthening and toughening of the parts. Heat treatment often results in deformation of thin-walled structures and increased cost. In order to improve the yield of thin-walled structural parts and reduce costs, the use of heat-free high-strength and tough aluminum alloys to pre...

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Problems solved by technology

[0004] At present, many production enterprises and research institutes disclose some heat-free die-casting aluminum alloys, such as CN104471090 B, CN105316542 A, CN10548365B, CN 106636787B and CN 110079712 A, etc. , these patents ensure the high fluidity, high strength and high toughness of the alloy by adding alloy elements such as Si, Mg, Cu, V, Zr, rare earth and Sr, but they do not mention the thermal stability of the alloy

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