A scandium-containing cast aluminum-lithium alloy and a preparation method thereof

Abstract

A novel scandium-containing cast aluminum-lithium alloy is disclosed. The alloy includes, by weight, 1.6-1.99% of Li, 0.9-1.9% of Cu, 0.2-0.7% of Mg, 0.1-0.25% of Zr, 0.05-0.35% of Sc, and impurity elements which are Fe, Si, Na, K and P, with the balance being Al, with the Fe content being less than 0.15% and the total content of the impurity elements being less than 0.25%. During preparation, Al-Cu and Al-Zr master alloys, pure aluminum, pure Mg and pure Li are smelted to obtain an aluminum alloy; then three stages of solid solution heat treatment are performed including solid solution heat treatment at 440-460 DEG C for 32 h, solid solution heat treatment at 510-520 DEG C for 24-32 h and solid solution heat treatment at 530-540 DEG C for 1-6 h; and after water quenching, artificial ageing treatment at 150-190 DEG C is performed for 16-48 h to obtain the novel scandium-containing cast aluminum-lithium alloy. The obtained novel scandium-containing cast aluminum-lithium alloy has a uniform microscopic structure, stable performance, density lower than density of traditional aluminum alloys, higher elastic modulus and rigidity, and other mechanical properties, and is low in cost. Theultimate tensile strength of the novel scandium-containing cast aluminum-lithium alloy can be 450-490 MPa and the specific elongation is 4.5-7.0%.

Description

technical field [0001] The invention belongs to the field of metal materials and metallurgy, and relates to a preparation method of cast aluminum-lithium alloy containing scandium, in particular to a method obtained by adding alloy elements (Li, Cu, Mg, Sc, Zr) and corresponding heat treatment process conditions A method for preparing a cast aluminum-lithium alloy with low density, high elastic modulus, and high strength and toughness. Background technique [0002] The rapid development of the aerospace field has put forward increasingly stringent requirements for aircraft, especially large civil aircraft manufacturing. Reducing the density of materials and improving the stiffness and damage tolerance of materials has become an important means to achieve breakthroughs in core technologies. Aluminum-lithium alloy is a lightweight alloy with low density, high strength, high stiffness and damage resistance. Studies have shown that for every 1wt% Li added to aluminum alloy, th...

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Problems solved by technology

[0003] There is a lack of research on casting aluminum-lithium alloys at home and abroad. In response to the urgent needs of reducing weight and improving rigidity of complex structural parts in the aerospace and military fields (such as missile cabins and torpedo shells, etc.), the development of mechanical properties and excellent casting properties , a new cast aluminum-lithium alloy with lower cost is imperative

The strength and elongation of the currently developed cast aluminum-lithium alloys are low, and it is difficult to match the strength of traditional cast high-strength aluminum alloys (ZL201, ZL205A)

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