A kind of high strength and toughness magnesium alloy and preparation method thereof

Abstract

The invention discloses a high-strength and tough magnesium alloy, which is characterized in that the mass percentage composition of the magnesium alloy is Sm: 1.7wt%-2.5wt%, Mn: 0.4wt%-0.8wt%, Ca: 0.2wt%-0.6wt% %, Zn: 0.2wt% to 0.6wt%, the balance being Mg and unavoidable impurities. In the present invention, by controlling the addition amount of Sm, Mg, Zn, Ca, and Mn, on the one hand: the rare earth Sm forms a large amount of MgZnCaSm and MgZnSm nanophases with Mg, Zn, and Ca, and there are also a large amount of α-Mn nanophases in the alloy structure , these nanophases play the role of strengthening the magnesium matrix, improving the strength of the alloy, and the size of the nanophase is small, can be dispersed on the magnesium alloy matrix, has little effect on the elongation of the matrix, and can realize the tensile strength of the magnesium alloy The strength is 400MPa-450MPa, the yield strength is 390MPa-420MPa, and the elongation is above 15%.

Description

technical field [0001] The invention belongs to the technical field of magnesium alloys, and in particular relates to a high-strength and toughness magnesium alloy and a preparation method thereof. Background technique [0002] As the lightest metal structural material, magnesium alloy has a series of advantages such as low density, high specific strength, good thermal conductivity and excellent damping and shock absorption performance. It has a wide range of application prospects in aerospace, transportation and mobile communications. However, the strength of traditional magnesium alloys is not high, leading to some challenges in practical applications. At present, researchers mainly control the microstructure of magnesium alloys by alloying, plastic deformation and heat treatment, in order to obtain new magnesium alloys with excellent comprehensive mechanical properties, and then meet the needs of practical applications. [0003] Studies have shown that adding rare earth ...

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Problems solved by technology

[0004] The patent (CN105088038A) proposes a high thermal conductivity and corrosion-resistant Mg-1.5~6%Sm-0.001~1.2%Ca-0.5~3.0%Zn-0.3~2.5%Mn alloy, and its extrusion deformation process is: the ingot is cast in 350-420°C for 2-24h homogenization treatment, extrusion speed 0.1-6mm / s, extrusion ratio 14-30, water quenching after extrusion, but no heat treatment process after extrusion deformation and mechanics after extrusion deformation The performance is explained; Guan Kai et al obtained fine dynamic recrystallization grains (~0.47m) by extrusion of Mg-3.5Sm-0.6Zn-0.5Zr alloy, and after further T5 aging treatment, the yield of the alloy The strength reached ~416MPa, and the elongation was ~5.1%. The patent (CN111485453.A) proposed a deformed magnesium alloy containing neodymium, samarium, light rare earth elements and high Mn content and its preparation method. The mass composition ratio is: calcium: 0.3-1.9%; aluminum: 0.3-1.5%; zinc: 0.2-1.7%; manganese: 0.3-2.8%; light rare earth (neodymium or samarium): 0.3-3.0%, the material can The tensile strength reaches 368-435MPa, and the elongation is 4-13%, but the disadvantage of this alloy is that the elongation of the patented alloy is less than 10% when the tensile strength reaches above 390MPa, showing obvious Mismatch of strength and plasticity

[0005] At present, high strength and low elongation at break are common problems in high-strength wrought magnesium alloy materials, which greatly limits its application. Therefore, the development of high strength and high elongation at break is of great significance to promote the application of magnesium alloy materials.

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