Low-alloy-content corrosion-resistant high-performance magnesium alloy and preparation method thereof

Abstract

The invention belongs to the technical field of metal materials, and discloses a low-alloy-content corrosion-resistant high-performance magnesium alloy and a preparation method thereof. The magnesium alloy comprises, by mass, 0.15%-0.55% of aluminum, 0.01%-0.5% of manganese, 0.03%-0.1% of calcium and the balance magnesium, additive elements and inevitable impurities, the additive elements are one or combination of tin, zinc, gadolinium and yttrium, and the adding amount of the additive elements is as follows: 0%-0.4% of tin, 0%-0.5% of zinc, 0%-0.35% of gadolinium and 0%-0.35% of yttrium. The preparation method comprises the steps of alloy smelting, pouring, homogenizing heat treatment and rapid extrusion. After the process, an atomic scale microstructure is formed in the magnesium alloy. The rare earth elements can change the components of the second-phase particles, reduce the micro galvanic corrosion of the microstructure and the magnesium matrix and remarkably improve the corrosion resistance, and can also interact with the zinc element to reduce the grain size; the tin element is dissolved in the magnesium matrix, the strength of weakening micro galvanic corrosion can be achieved, the corrosion resistance is improved, and meanwhile the deformation capacity of the magnesium alloy can be improved through the trace tin element.

Description

technical field [0001] The invention relates to the field of metal materials, in particular to a low-alloy content corrosion-resistant high-performance magnesium alloy and a preparation method thereof. Background technique [0002] As the lightest metal structural material, magnesium alloy has the advantages of high specific strength, good shock absorption and good electromagnetic shielding, so it has a wide range of application prospects in the fields of automobile, aerospace, 3C products and so on. The preparation of magnesium alloy sheets usually requires steps such as smelting, homogenization heat treatment, extrusion, and post-treatment. Among them, the main purpose of homogenization heat treatment before extrusion and solution treatment in post-treatment is to eliminate component segregation in the alloy. , to obtain a billet with a uniform structure. However, the heat treatment of alloy materials generally requires high temperature and takes a long time, which not on...

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Problems solved by technology

However, the heat treatment of alloy materials generally requires high temperature and takes a long time, which not only elongates the production process of magnesium alloy sheets, but also greatly increases the consumption of energy, which limits the wide application of magnesium alloys to a certain extent. application

[0003] In the prior art, CN 100591786 C discloses a wrought magnesium alloy for high-speed extrusion, the composition of alloy elements is: Al: 5-7%, Zn: 2-3%, Mn: 7-9%, Li : 3-4%, Zr: 1-3%, the rest is magnesium and unavoidable impurities, the yield strength of the final extruded profile is 142-178MPa, the tensile strength is 248-275MPa, although the extrusion speed of the alloy The maximum can reach 20m / min, but it needs to be kept at 450-500°C for 2-3 hours before extrusion, which consumes a lot of energy, and the added elements are as high as 26%, which is very high, which will significantly increase production costs. The addition of too much manganese is also detrimental to the corrosion resistance of the alloy; Fu Xiaoyu et al. published in 2021 in the journal "Journal of Nonferrous Metals", Volume 31, Issue 7, pages 1789-1808, entitled "Rare Earth Effects on AZ91 Magnesium Alloy Influence of Corrosion Behavior" mentioned in the article that the alloy added with 0.4% (La, Ce) and 1.0% (La, Ce) was immersed in 3.5% sodium chloride solution for 11 hours, and the amount of hydrogen evolution was 15-20mL / cm 2 Between, and the addition of 0.9% Y alloy under the same conditions, the amount of hydrogen evolution is about 12mL / cm 2 , it can be seen that the existing technology improves the corrosion resistance of magnesium alloys by adding a large amount of rare earth alloys. From the perspective of industrial production, this will greatly increase the production cost