CN-121992261-A - Microalloying rapid extrusion flame-retardant magnesium alloy and preparation method thereof

Abstract

The invention discloses a micro-alloyed rapid extrusion flame-retardant magnesium alloy and a preparation method thereof, and belongs to the technical field of metal materials. The micro-alloyed rapid extrusion flame-retardant magnesium alloy consists of, by mass, 1.0-1.8% of aluminum, 0.3-0.4% of calcium, 0.4-0.6% of manganese, 0-0.08% of nano particles, less than or equal to 0.02% of unavoidable impurities, and the balance of magnesium. The high Wen Shigai is oxidized preferentially to form a dense CaO layer to block oxygen, the ignition point of the alloy is obviously improved, the high-density nano phase is separated out dynamically in the rapid extrusion process of aluminum and manganese, the grain boundary is effectively pinned, the coarsening of grains is restrained, the stability of a microstructure below an oxide film is enhanced, the nano particles are combined with ultrasonic melt treatment to refine the structure, and meanwhile microscopic defects of the surface oxide film are filled, so that the self-repairing capability and compactness of the surface oxide film are improved. The design realizes the collaborative optimization of low production cost, good flame retardant property and high-efficiency extrusion capability of the alloy through the cooperation of micro-alloying design (the total element content is less than or equal to 2.8 percent) and nano-particle reinforcement and a rapid extrusion process, and has wide industrialization prospect.

Inventors

• WANG CHENG
• YANG ZHI
• NING HONG
• WANG HUIYUAN
• GUAN KAI
• WANG XUAN
• YANG ZHIZHENG
• ZHOU XIAOLI

Assignees

• 吉林大学

Dates

Publication Date

20260508

Application Date

20260123

Claims (10)

1. 1. A micro-alloyed quick-extrusion flame-retardant magnesium alloy is characterized by comprising, by mass, 1.0-1.8% of aluminum, 0.3-0.4% of calcium, 0.4-0.6% of manganese, 0-0.08% of nano particles, less than or equal to 0.02% of unavoidable impurities and the balance of magnesium.
2. 2. The micro-alloyed rapid extrusion flame retardant magnesium alloy of claim 1, wherein the nanoparticles comprise titanium carbide nanoparticles and/or titanium diboride nanoparticles.
3. 3. The micro-alloyed rapid extrusion flame-retardant magnesium alloy according to claim 1, wherein the content of alloying elements of the micro-alloyed rapid extrusion flame-retardant magnesium alloy is less than or equal to 2.8%, and belongs to a low alloy system.
4. 4. A method for preparing a micro-alloyed rapid extrusion flame retardant magnesium alloy according to any one of claims 1-3, comprising the steps of: S1, weighing raw materials according to the components in percentage by mass; Wherein the magnesium, aluminum, calcium, manganese, and nanoparticles are derived from pure magnesium, pure aluminum, magnesium-calcium master alloy, magnesium-manganese master alloy, titanium carbide/aluminum master alloy, titanium diboride/aluminum master alloy; S2, adding pure aluminum, magnesium-calcium intermediate alloy and magnesium-manganese intermediate alloy after melting pure magnesium until the pure aluminum, magnesium-calcium intermediate alloy and magnesium-manganese intermediate alloy are completely melted, then removing slag and stirring, then blowing high-purity argon for refining and removing slag after heat preservation, adding titanium carbide/aluminum intermediate alloy and/or titanium diboride/aluminum intermediate alloy after heating again, carrying out melt ultrasonic treatment after all the magnesium intermediate alloy is melted, and removing slag again to obtain a low-alloy magnesium alloy melt; S3, pouring the micro-alloyed magnesium alloy melt into a steel mold to obtain a micro-alloyed magnesium alloy cast ingot; s4, homogenizing the microalloyed magnesium alloy cast ingot, extruding and deforming, and air-cooling to room temperature to obtain the microalloyed quick extrusion flame-retardant magnesium alloy.
5. 5. The method according to claim 4, wherein the magnesium-calcium intermediate alloy in S1 is Mg-20Ca and the magnesium-manganese intermediate alloy is Mg-3Mn.
6. 6. The method according to claim 4, wherein the titanium carbide/aluminum master alloy in S1 is Al-5Ti-0.2C, and the titanium diboride/aluminum master alloy is Al-5Ti-1B.
7. 7. The method according to claim 4, wherein the temperature of the reheating in S2 is 680-720 ℃.
8. 8. The method according to claim 4, wherein the parameters of the ultrasonic treatment of the melt in S2 are immersion depth of 30mm, ultrasonic power of 1200W and ultrasonic time of 120S.
9. 9. The method according to claim 4, wherein the homogenizing treatment in S4 is specifically carried out by carrying out three-stage step homogenizing treatment of 330 ℃/4h+450 ℃/3h+480 ℃/1h on the micro-alloyed magnesium alloy cast ingot in a muffle furnace, and then carrying out water quenching.
10. 10. The method according to claim 4, wherein the extrusion deformation treatment in S4 is specifically performed by preheating the homogenized microalloyed magnesium alloy ingot at 300-400 ℃ for 60-120min and preheating the extrusion die at 300-400 ℃ before extrusion deformation, wherein the extrusion ratio is (10-70): 1, and the extrusion outlet rate is 5-30m/min.

Description

Microalloying rapid extrusion flame-retardant magnesium alloy and preparation method thereof Technical Field The invention belongs to the technical field of metal materials, and particularly relates to a micro-alloyed rapid extrusion flame-retardant magnesium alloy and a preparation method thereof. Background Magnesium alloy has obvious advantages in the field of engineering materials due to low density, high specific strength and specific stiffness, excellent damping and shock absorption performance and electromagnetic shielding property. In the existing commercial magnesium alloy products, a magnesium-aluminum alloy system still takes the dominant role, wherein the alloys such as AZ91, AZ31, AZ80 and the like become the magnesium alloy series with the most wide application due to the cost advantage and the room temperature mechanical property performance. However, the magnesium alloy cast structure generally has coarse grains, is easy to have casting defects such as looseness, shrinkage cavity and the like, is easy to crack in a high-speed extrusion process, and generally ensures formability by reducing extrusion speed, so that the magnesium alloy cast structure has low extrusion efficiency, high energy consumption and high processing cost, and the factors limit the application of the magnesium alloy cast structure as a main bearing structural material. With the rapid development of new energy automobile technology, especially the safety requirements on key components such as battery packs, electric drive systems and the like are continuously improved, and the flame retardant property of the material becomes a core index for guaranteeing the safety and reliability of vehicles. Currently, the key parts of new energy automobiles require materials with higher flame retardant grades and longer thermal runaway delay time, so that the improvement of the flame retardant property of magnesium alloy becomes an important direction of industry research. However, the application range of the traditional commercial magnesium-aluminum alloy is severely limited due to lower ignition point and easy oxidation combustion under high-temperature environment, especially in key parts such as battery packs with extremely high safety requirements. Therefore, developing a novel magnesium alloy material with low production cost, good flame retardant property and high efficient extrusion capability has become a key technical problem to be solved by those skilled in the art. The breakthrough of the technology is expected to expand the application range of the magnesium alloy in a plurality of fields, and further promotes the development of light-weight design, energy conservation and emission reduction. Disclosure of Invention In view of the above, the invention aims to provide a micro-alloying rapid extrusion flame-retardant magnesium alloy and a preparation method thereof, and the balance of low cost, high flame retardance and high formability of the magnesium alloy is realized on the premise of not adding rare earth elements by the cooperation of a micro-alloying design, a nanoparticle reinforcement and ultrasonic melt processing preparation process and a rapid extrusion process, so that the magnesium alloy is suitable for the fields with high requirements on safety and light weight, such as new energy automobile battery packs, aerospace and the like. In order to achieve the above object, the present invention provides the following technical solutions: The invention provides a micro-alloyed rapid extrusion flame-retardant magnesium alloy which comprises, by mass, 1.0-1.8% of aluminum, 0.3-0.4% of calcium, 0.4-0.6% of manganese, 0-0.08% of nano particles, less than or equal to 0.02% of unavoidable impurities, and the balance of magnesium. Preferably, the nanoparticles comprise titanium carbide nanoparticles and/or titanium diboride nanoparticles. The nano particles are used as heterogeneous nucleation cores, the microstructure is obviously refined, the nano particles are uniformly dispersed in a melt through ultrasonic melt treatment, the nucleation efficiency is improved, and the micro defects are migrated and filled into the surface oxide layer at high temperature, so that oxygen is effectively blocked. Preferably, the content of alloying elements in the micro-alloyed rapid extrusion flame-retardant magnesium alloy is less than or equal to 2.8%, and the micro-alloyed rapid extrusion flame-retardant magnesium alloy belongs to a low alloy system. The alloy prepared by the invention avoids brittle phase increase caused by excessive alloy elements, and is beneficial to rapid extrusion. The invention also provides a preparation method of the micro-alloyed rapid extrusion flame-retardant magnesium alloy, which comprises the following steps: S1, weighing raw materials according to the components in percentage by mass; Wherein the magnesium, aluminum, calcium, manganese, and nanoparticles are derived from pure magnesium, pure aluminum,