CN-121992264-A - High-strength low-thermal-expansion magnesium alloy and preparation method and application thereof

Abstract

The invention belongs to the technical field of alloy casting, and relates to a high-strength low-thermal expansion magnesium alloy, a preparation method and application thereof; the magnesium alloy comprises the following components by weight percent, namely, 14-16% of Y, 4.5-5.5% of Cu and the balance of Mg; the invention also discloses a preparation method of the magnesium alloy, which comprises the steps of alloy raw material proportioning, smelting and alloying, melt processing and quenching to obtain a magnesium alloy product, wherein the magnesium alloy has excellent room temperature mechanical property and extremely low thermal expansion coefficient, is particularly suitable for manufacturing precise components which need to keep high dimensional stability, light weight and high specific strength in a wide temperature range, such as satellite optical platform components, train track fastener systems, natural gas storage tank connecting pipeline systems, new energy automobile battery shells, inertial navigation system frames, high-precision aerospace sensor shells, photoetching machine workpiece table components, high-end communication equipment shielding covers or radiating substrates and the like, and has huge application prospects.

Inventors

• WU SUJUAN
• HUANG YADONG
• DENG GUANCHENG
• GU KAIJIE
• LIU XUDONG
• SONG JIANGFENG
• JIANG BIN

Assignees

• 重庆大学
• 明月湖实验室

Dates

Publication Date

20260508

Application Date

20260226

Claims (6)

1. 1. The magnesium alloy with high strength and low thermal expansion is characterized by comprising the following components, by weight, 14-16% of Y, 4.5-5.5% of Cu and the balance of Mg.
2. 2. The high-strength low-thermal-expansion magnesium alloy according to claim 1, wherein the magnesium alloy comprises the following components in percentage by weight.
3. 3. The method for producing a high-strength low-thermal expansion magnesium alloy according to any one of claims 1 to 2, comprising: preparing raw materials according to the weight percentage of magnesium alloy components, wherein Mg is added in the form of pure magnesium ingots, cu is added in the form of pure copper blocks, and Y is added in the form of Mg-Y intermediate alloy; Heating a pure magnesium ingot to be completely melted in the environment of protective gas, preserving heat at 740-780 ℃ for 15-20 min, sequentially adding an Mg-Y intermediate alloy and pure copper, uniformly stirring, preserving heat and standing for 30-45 min to obtain a melt; And (3) stabilizing the temperature of the melt in the range of 740-760 ℃ and carrying out water cooling quenching to obtain the alloy.
4. 4. The method for preparing a high-strength low-thermal-expansion magnesium alloy according to claim 3, wherein the shielding gas is mixed gas of SF 6 and CO 2 or high-purity argon, and the volume ratio of SF 6 to CO 2 in the mixed gas of SF 6 and CO 2 is 1:199.
5. 5. Use of the high strength low thermal expansion magnesium alloy according to any of claims 1-2 for maintaining high stability, light weight and high specific strength of material parts over a wide temperature range.
6. 6. The use of claim 5, wherein the components comprise satellite optical platform components, train track fastener systems, natural gas tank connection tubing systems, new energy automobile battery enclosures, inertial navigation system frames, high precision aerospace sensor housings, lithography machine workpiece stage components, and/or high end communications device shields or heat dissipating substrates.

Description

High-strength low-thermal-expansion magnesium alloy and preparation method and application thereof Technical Field The invention relates to the technical field of alloy casting, and relates to a high-strength low-thermal expansion magnesium alloy, a preparation method and application thereof. Background Magnesium alloy is used as the lightest commercial metal engineering material, the density of the magnesium alloy is about 1.74 g/cm3, and the density is respectively 2/3 of that of aluminum alloy and 1/4 of that of steel, and the magnesium alloy has remarkable advantages in the aspect of light structure. However, the conventional magnesium alloy such as AZ91D, AM B generally has the problems of low absolute strength, weak high-temperature creep resistance, poor corrosion resistance, higher thermal expansion coefficient (usually 25-28×10 -6/K) and the like, the higher thermal expansion coefficient leads to poor thermal dimensional stability, and is not matched with the thermal expansion coefficient of a common metal material, so that stress concentration and failure at a joint are easily caused, the conventional alloying or low/negative thermal expansion phase adding method reduces the thermal expansion coefficient of the magnesium alloy, but the excessive adding amount can damage the mechanical property and light quality of the magnesium alloy, and severely limits the application of the magnesium alloy in the precision engineering field requiring high dimensional stability. Therefore, there is a need in the art for a magnesium alloy material that can achieve both high strength and low coefficient of thermal expansion while maintaining good castability and plasticity. Disclosure of Invention The invention aims at solving the problem that the magnesium alloy material in the prior art cannot simultaneously realize high strength and low thermoplasticity, and provides a magnesium alloy material with high strength, high plasticity, low density and low thermal expansion. The second object of the invention is to provide a preparation method of the magnesium alloy material with high strength and low thermal expansion. A third object of the present invention is to provide an application of a high-strength low-thermal expansion magnesium alloy material in a component material maintaining high stability, light weight and high specific strength in a wide temperature range. In order to achieve the first invention purpose, the invention can be realized by the following technical scheme that the high-strength low-thermal expansion magnesium alloy comprises the following components in percentage by weight. The technical scheme has the beneficial effects that magnesium is used as a matrix, and the alloy is subjected to alloying design through yttrium (Y) and copper (Cu) with specific contents, so that the Mg-Y-Cu alloy with excellent room temperature mechanical properties and extremely low Coefficient of Thermal Expansion (CTE) is obtained, and the alloy is particularly suitable for manufacturing parts which need to keep high dimensional stability, light weight and high specific strength in a wide temperature range, such as satellite optical platforms, inertial navigation system frames, train track fasteners, natural gas storage tank connecting pipeline systems, new energy automobile battery shells, high-precision aerospace sensor shells, photoetching machine work-table parts and/or high-end communication equipment shielding covers, radiating substrates and the like. According to the invention, the comprehensive performance of the magnesium alloy can be effectively improved by adding the rare earth element, yttrium is taken as an important heavy rare earth element, the crystal grains of the magnesium alloy can be obviously refined, and a second phase (such as Mg 24Y5) with high thermal stability is formed, so that the temperature and high-temperature strength of the magnesium alloy are improved; in addition, the rare earth element Y with specific content is added on the basis of the specific content of magnesium element and copper element, a certain long-period stacking ordered structure (LPSO) is formed inside the alloy body, and the long-period stacking ordered (LPSO) phase passes through L 12 type strong bonding atomic clusters (such as Y 8Cu6) on the atomic scale and the long-period stacking structure, so that the interatomic bonding force and the rigidity of the crystal structure are enhanced; in the microstructure of the invention, LPSO laths or reticular structures and magnesium base form a coherent interface to form a biphase composite system, thus not only improving mechanical properties through a load transfer mechanism, but also generating a constraint effect on thermal expansion of the magnesium base by an interface strain field. In addition, the LPSO phase can activate non-basal plane slip, has kink deformation capability, improves plasticity and toughness while maintaining high strength, has high thermal stabil