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CN-121992263-A - High-strength heat-resistant magnesium alloy and preparation method thereof

CN121992263ACN 121992263 ACN121992263 ACN 121992263ACN-121992263-A

Abstract

The invention provides a high-strength heat-resistant magnesium alloy and a preparation method thereof, and relates to the technical field of alloys. The high-strength heat-resistant magnesium alloy comprises, by mass, 3.0-3.5% of Gd, 0.8-1.2% of Zn, 0.3-0.5% of Zr, 1.0-4.0% of Nd and the balance of Mg. The high-strength heat-resistant magnesium alloy provided by the invention has high mechanical properties at room temperature, still keeps high mechanical properties at a high temperature of 150-250 ℃ (the tensile strength at 250 ℃ can reach 234+/-1 MPa, the yield strength can reach 194+/-6 MPa, the elongation can reach 15.0+/-1.4%), and also has excellent mechanical properties even in an application scene of 300 ℃, and the addition of rare earth elements is greatly reduced, so that the weight of the magnesium alloy is ensured, the alloy cost is reduced, and in addition, the magnesium alloy also has excellent casting performance.

Inventors

  • TAN JUN
  • TAO ZHIYUAN
  • LIU XU
  • ZHOU YIGE

Assignees

  • 上海铸米科技有限公司
  • 陕西轻一点材料科技有限公司

Dates

Publication Date
20260508
Application Date
20260226

Claims (10)

  1. 1. The high-strength heat-resistant magnesium alloy is characterized by comprising the following components in percentage by mass: 3.0-3.5% of Gd, 0.8-1.2% of Zn, 0.3-0.5% of Zr, 1.0-4.0% of Nd and the balance of Mg.
  2. 2. The high-strength heat-resistant magnesium alloy according to claim 1, which is characterized by comprising the following components, by mass, 3.2-3.4% of Gd, 0.8-1.1% of Zn, 0.3-0.5% of Zr, 1.2-3.6% of Nd and the balance of Mg.
  3. 3. The high-strength heat-resistant magnesium alloy according to claim 2, which is characterized by comprising the following components, by mass, 3.22-3.34% of Gd, 0.86-1.03% of Zn, 0.37-0.5% of Zr, 1.2-3.57% of Nd and the balance of Mg.
  4. 4. The high-strength heat-resistant magnesium alloy according to claim 3, which comprises the following components in percentage by mass.
  5. 5. The method for preparing the high-strength heat-resistant magnesium alloy according to any one of claims 1 to 4, which is characterized by comprising the following steps: Mixing magnesium, zinc, magnesium gadolinium intermediate alloy, magnesium neodymium intermediate alloy and magnesium zirconium intermediate alloy, and smelting to obtain a first alloy liquid; Mixing the first alloy liquid with a refining agent for refining to obtain a second alloy liquid; And after casting and forming the second alloy liquid, sequentially carrying out solution treatment and aging treatment to obtain the high-strength heat-resistant magnesium alloy, wherein the temperature of the solution treatment is 505-515 ℃, the heat preservation time is 4-12 h, the temperature of the aging treatment is 222-228 ℃, and the heat preservation time is 4-24 h.
  6. 6. The preparation method according to claim 5, wherein the smelting method comprises the following steps: mixing magnesium and magnesium gadolinium intermediate alloy for first smelting to obtain Mg-Gd alloy liquid; and adding zinc, magnesium neodymium intermediate alloy and magnesium zirconium intermediate alloy into the Mg-Gd alloy liquid, and carrying out second smelting to obtain the first alloy liquid, wherein the temperature of the first smelting and the second smelting is 750 ℃.
  7. 7. The preparation method of the magnesium alloy according to claim 5, wherein the refining agent is a magnesium alloy refining agent with a granularity of 20 μm-0.5 mm, the mass of the refining agent is 1% of the mass of the first alloy liquid, and the refining temperature is 720 ℃.
  8. 8. The production method according to claim 5, wherein a rate of temperature rise to the solution treatment temperature is 5 to 10 ℃.
  9. 9. The production method according to claim 5, wherein the rate of temperature rise to the temperature of the aging treatment is 5 to 10 ℃.
  10. 10. The method according to claim 5, wherein the smelting, refining, casting, solution treatment and aging treatment are performed in a protective atmosphere, wherein the protective atmosphere is a mixed gas of CO 2 and SF 6 , and the volume fraction of CO 2 in the mixed gas is 99%.

Description

High-strength heat-resistant magnesium alloy and preparation method thereof Technical Field The invention relates to the technical field of alloys, in particular to a high-strength heat-resistant magnesium alloy and a preparation method thereof. Background The magnesium alloy has the advantages of low density, high specific strength, good thermal conductivity and the like, and has wide application prospect. However, magnesium alloys have low strength at high temperatures, which makes them not suitable for use in high Wen Fuyi scenes such as automobile engines, aerospace components, etc. Currently, in order to obtain a high-strength heat-resistant magnesium alloy, a method of adding a large amount of rare earth elements to the magnesium alloy is generally adopted. Although the method can obviously improve the strength and heat resistance of the magnesium alloy, rare earth elements are expensive, so that the material cost is greatly increased, and the wide application of the magnesium alloy is restricted. For example, commercial WE54 alloy has the rare earth element content of more than 9wt%, has high cost, and is easy to generate defects such as dendrite segregation in the casting process. In addition, because the light rare earth element and the heavy rare earth element are both high in atomic number, the density is generally higher than that of metal magnesium, and the addition of excessive rare earth elements also increases the density of the magnesium alloy, so that the expectations and prospects of the lightweight application of the magnesium alloy are reduced. In particular, existing high-strength heat-resistant magnesium alloys tend to be more concerned with the improvement of tensile strength and yield strength, while neglecting the improvement of elongation. When a metal material has high tensile strength and yield strength, but low elongation, it is generally called a high-strength low-plasticity material, and a series of serious problems are brought to practical application, including high brittle failure risk, low impact toughness, difficult processing and forming, low fatigue performance and strong stress corrosion sensitivity, so that the material application is limited. The relationship between strength and elongation (plasticity) is that, how to obtain heat-resistant magnesium alloy with high strength and high plasticity is a challenging technical problem at present. Disclosure of Invention In view of the above, the present invention aims to provide a high-strength heat-resistant magnesium alloy and a preparation method thereof. The magnesium alloy provided by the invention has low rare earth content and excellent high-temperature mechanical properties (high tensile strength, yield strength and elongation). In order to achieve the above object, the present invention provides the following technical solutions: the invention provides a high-strength heat-resistant magnesium alloy which comprises the following components in percentage by mass: 3.0-3.5% of Gd, 0.8-1.2% of Zn, 0.3-0.5% of Zr, 1.0-4.0% of Nd and the balance of Mg. Preferably, the high-strength heat-resistant magnesium alloy comprises, by mass, 3.2-3.4% of Gd, 0.8-1.1% of Zn, 0.3-0.5% of Zr, 1.2-3.6% of Nd and the balance of Mg. Preferably, the high-strength heat-resistant magnesium alloy comprises, by mass, 3.22-3.34% of Gd, 0.86-1.03% of Zn, 0.37-0.5% of Zr, 1.2-3.57% of Nd and the balance of Mg. Preferably, the high-strength heat-resistant magnesium alloy comprises the following components in percentage by mass of 3.34% of Gd, 0.86% of Zn, 0.48% of Zr, 2.42% of Nd and the balance of Mg. The invention provides a preparation method of the high-strength heat-resistant magnesium alloy, which comprises the following steps: Mixing magnesium, zinc, magnesium gadolinium intermediate alloy, magnesium neodymium intermediate alloy and magnesium zirconium intermediate alloy, and smelting to obtain a first alloy liquid; Mixing the first alloy liquid with a refining agent for refining to obtain a second alloy liquid; And after casting and forming the second alloy liquid, sequentially carrying out solution treatment and aging treatment to obtain the high-strength heat-resistant magnesium alloy, wherein the temperature of the solution treatment is 505-515 ℃, the heat preservation time is 4-12 h, the temperature of the aging treatment is 222-228 ℃, and the heat preservation time is 4-24 h. Preferably, the smelting method comprises the following steps: mixing magnesium and magnesium gadolinium intermediate alloy for first smelting to obtain Mg-Gd alloy liquid; and adding zinc, magnesium neodymium intermediate alloy and magnesium zirconium intermediate alloy into the Mg-Gd alloy liquid, and carrying out second smelting to obtain the first alloy liquid, wherein the temperature of the first smelting and the second smelting is 750 ℃. Preferably, the refining agent is a magnesium alloy refining agent with granularity of 20-0.5 mm, the mass of the refin