Method for preparing magnesium alloy

Abstract

The invention provides a method for preparing a magnesium alloy. The method comprises the following: solution treatment process: heating a cast magnesium alloy to 350 to 550 DEG C and performing heat preservation treatment, wherein the cast magnesium alloy has the following atomic ratio composition: Mg1-a-bREaZrb, wherein RE is one or more of Y, Sc, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu; a is equal to or more than 1 percent and equal to or less than 6 percent; b is equal to or more than 0.05 percent and equal to or less than 0.5 percent; hot extrusion process, performing heat extrusion on the magnesium alloy subjected to the heat preservation treatment at the temperature of between 350 and 550 DEG C and then fast cooling the obtained product to the room temperature; cold rolling process, performing cold rolling on the magnesium alloy subjected to the heat extrusion at the rolling reduction of 5 to 50 percent; and ageing process, performing ageing treatment on the magnesium alloy subjected to the cold rolling. The yield strength of the prepared Mg-Gd-Zr alloy reaches 447MPa.

Description

technical field [0001] The invention relates to the technical field of metal materials, in particular to a preparation method of a magnesium alloy. Background technique [0002] Magnesium alloy is currently a relatively light metal material, with high specific strength and specific stiffness, good antimagnetic, electronegativity, thermal conductivity, shock absorption and cutting performance, etc., but the strength of magnesium alloy is low , poor heat resistance, which limits its application. [0003] The difference between the atomic size radius of most rare earth elements and magnesium is within ±15%. They have a large solid solubility in magnesium and have good solid solution strengthening and precipitation strengthening effects. Therefore, adding rare earth elements to magnesium alloys to form Rare earth magnesium alloys can effectively improve the microstructure and microstructure of magnesium alloys, improve the strength, heat resistance, and corrosion resistance of ...

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Problems solved by technology

[0004] Rare earth magnesium alloys with high strength, heat resistance and corrosion resistance can be obtained after smelting, solid solution and aging of rare earth, magnesium and other metals, but their yield strength is still low, which cannot meet the actual needs of engineering

The present inventors have found through research that the rare earth-containing magnesium alloy is subjected to solution treatment including three processes of heating, heat preservation and quenching or solution treatment including two processes of heating and heat preservation, and then subjected to hot extrusion and aging treatment to obtain The yield strength of the magnesium alloy has been improved, but the increase rate is relatively low. The reason is as follows: After the alloy undergoes solution treatment including quenching step and then hot extruded, the grain size can be refined to a certain extent, but in In the alloy after quenching, the rare earth elements are in a supersaturated state. After hot extrusion, a large amount of rare earth elements are precipitated, resulting in a decrease in the number of metastable phases precipitated during aging treatment, which makes the yield strength of the alloy increase to a low degree; After the hot extrusion of the unquenched magnesium alloy in the solution treatment, the degree of refinement of the alloy grains is low, resulting in that the size of the metastable phase precipitated by aging will not be significantly refined, and the yield strength of the alloy will increase slightly.

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