CN-121992262-A - High-performance die-casting magnesium rare earth alloy and preparation method thereof

Abstract

The invention provides a high-performance die-casting magnesium rare earth alloy and a preparation method thereof. The die-casting magnesium rare earth alloy comprises the following components in percentage by weight of 5-15% of RE, 0.5-3% of X and the balance of Mg, wherein RE comprises at least one of Gd, Y, la, nd, sm, and X comprises at least one of Zn, mn and Zr. The die-casting magnesium rare earth alloy is prepared through smelting, pressure casting and heat treatment. The invention solves the problem that the crystal grains are easy to be coarse in the traditional casting process, obtains the fine-grain structure through the die casting technology, further optimizes the structure through the proper heat treatment technology, realizes the cooperative promotion of strength and plasticity, successfully prepares the Mg-RE-X magnesium rare earth alloy material with fine crystal grains, high strength and high plasticity, and can meet the urgent demands of the fields of aerospace, rail transit and the like on the light, high strength and high plasticity magnesium rare earth material.

Inventors

• WU YUJUAN
• HE BOWEN
• DING WENJIANG
• JIN YUHAO
• PENG LIMING
• DING CHENYANG
• HAN XIAO
• LI XIYU
• DENG QINGCHEN
• Wu Qianye
• LIANG YAOYUAN

Assignees

• 上海交通大学

Dates

Publication Date

20260508

Application Date

20241107

Claims (10)

1. 1. The high-performance die-casting magnesium rare earth alloy is characterized by comprising the following components in percentage by weight of 5-15% of RE, 0.5-3% of X and the balance of Mg; wherein RE comprises at least one of Gd, Y, la, nd, sm, and X comprises at least one of Zn, mn and Zr.
2. 2. The high-performance die-casting magnesium rare earth alloy according to claim 1, wherein the die-casting magnesium rare earth alloy comprises 9-13wt.% of RE, 1-2wt.% of X and the balance of Mg.
3. 3. The high performance die cast magnesium rare earth alloy according to claim 1 or 2, wherein RE is at least one of Gd, Y; and X is Zn or Mn.
4. 4. The high-performance die-casting magnesium rare earth alloy according to claim 3, wherein RE is Gd and Y, and the mass ratio of Gd to Y is 2-3.5:1.
5. 5. The high-performance die-casting magnesium rare earth alloy according to claim 3, wherein the mass ratio of Zn to Mn is 2-10:1.
6. 6. A method for preparing the high-performance die-casting magnesium rare earth alloy according to any one of claims 1 to 5, characterized in that the method comprises the following steps: A. selecting intermediate alloy and/or single metal according to the design components of the magnesium rare earth alloy, and weighing; B. smelting the intermediate alloy and/or single metal after proportioning in die casting equipment, and homogenizing and purifying the intermediate alloy and/or single metal by stirring, deslagging and standing; C. taking the molten magnesium-rare earth alloy formed after smelting in the step B as a raw material for die casting to obtain a die casting; D. and performing heat treatment on the die casting to obtain the high-performance die-casting magnesium rare earth alloy.
7. 7. The method for preparing high-performance die-casting magnesium rare earth alloy according to claim 6, wherein in the step A, the intermediate alloy is binary alloy or single metal.
8. 8. The method for preparing high-performance die-casting magnesium rare earth alloy according to claim 6, wherein in the step B, the smelting process needs to ensure the environment to be dry, the molten liquid needs to be protected by inert gas, and the total smelting time is not more than 5 hours; The temperature during the smelting process is at most 780 ℃ and at least above the melting point of all master alloys and/or single metals.
9. 9. The method for preparing the high-performance die-casting magnesium-rare earth alloy according to claim 6 is characterized in that in the step C, the magnesium-rare earth alloy melt is required to be an upper-layer melt in a melting furnace, the temperature range of die casting of the magnesium-rare earth alloy melt is 680-740 ℃, and the pressure value adopted by die casting is 80-100 MPa; the temperature of the die used for die casting is 240-260 ℃.
10. 10. The method for producing a high-performance die-cast magnesium rare earth alloy according to claim 6, wherein in step D, the heat treatment includes a solution treatment and an aging treatment; The temperature of the solution treatment is 480-530 ℃ and the time is 0-30 h, the temperature of the aging treatment is 150-250 ℃ and the time is 0-256 h.

Description

High-performance die-casting magnesium rare earth alloy and preparation method thereof Technical Field The invention relates to the technical field of magnesium alloy pressure casting, in particular to a high-performance die-casting magnesium rare earth alloy and a preparation method thereof. In particular to a high-performance magnesium rare earth alloy material prepared by adding rare earth alloy elements and other non-rare earth elements including Mn, zn and the like and adopting a subsequent heat treatment system. Background Magnesium is the lightest structural material. Magnesium alloys are widely used in the field of aviation, automotive, electronic and other high performance engineering due to their low density and good mechanical properties. However, the conventional magnesium alloy is limited in application due to low strength and low plasticity. In the solidification process of magnesium alloy melt, the gravity casting technology has the advantages of slower cooling speed, longer cooling time, difficult improvement of strength and plasticity, and limitation of the application range of magnesium alloy materials due to a series of problems of coarse grains, component segregation and the like. The die casting technology is mainly used for solving the problem of mass production of automobile parts and parts with complex shapes. The magnesium alloy molten liquid can be quickly injected into a cavity under the action of pressure, so that the magnesium alloy molten liquid is quickly solidified and molded. The technology has the greatest advantage that the technology can realize the rapid cooling solidification of molten metal, and obtain fine-sized grains and tissues with uniform components. Through the die casting technology, the die casting temperature of the magnesium alloy can be accurately controlled. Currently, commercial die-casting magnesium alloy mostly adopts an AZ (Mg-Al-Zn) system, and the main advantages of the system are good plasticity, but limited strength, and compared with the Mg-RE system, the strengthening means are insufficient. For example, patent CN118241091a is a typical AZ system alloy, but the tensile strength of the examples does not exceed 260MPa, and it is difficult to meet the higher strength requirements. Rare earth elements are a common alloying element of magnesium alloys. The addition of rare earth is beneficial to solid solution strengthening and age hardening of magnesium alloy, improves the strength of magnesium alloy, and forms a reinforcing phase beneficial to the promotion of strong plasticity. Zn and other elements are added into the rare earth magnesium alloy, so that the stacking fault energy can be reduced, and the formation of long-period stacking ordered structures (LPSO) and other reinforced structures is facilitated. However, we note that rare earth addition is often less in the current partial die-casting magnesium alloy, and the addition of rare earth tends to improve brittleness of the magnesium alloy, influence flowability in the casting process and needs to be eliminated by a certain technical means. For example, in patent CN118345290a, the rare earth addition amount is not more than 1.5%, but the final strength is not high. Disclosure of Invention The invention aims to comprehensively utilize the advantages of a die casting technology and a magnesium rare earth alloy and provides a high-performance die casting magnesium rare earth alloy and a preparation method thereof. Specifically, the invention develops a Mg-RE-X magnesium rare earth alloy material with high strength and plasticity, and the magnesium alloy cast structure with fine grains is obtained by utilizing an alloying means and a die casting technology, and the grain size does not obviously grow after heat treatment. Solves the problems of coarse grains, low strength and plasticity and the like of the Mg-RE material in the traditional casting process, obviously improves the comprehensive performance of the material, and meets the urgent requirements of the fields of aerospace, rail transit and the like on high-performance light materials. The Mg-RE-X magnesium rare earth alloy material prepared by the method has excellent comprehensive mechanical properties, is convenient to manufacture, has a simple heat treatment process, and can meet urgent requirements of the fields of aerospace, rail transit and the like on the light high-strength magnesium alloy material. The Mg-Gd-Y-Zn-Mn system magnesium alloy with obvious performance advantages is also used in the die casting process for the first time. The invention adds X element (such as Mn, zn, zr, etc.) in the die-casting magnesium rare earth alloy, improves the microstructure of the alloy, thereby obviously improving the mechanical property and the comprehensive performance of the magnesium rare earth alloy material, in particular the tensile strength and the elongation percentage. The invention is realized by the following technical scheme: In