Flame-proof magnesium alloy added with beryllium and strontium and preparation method thereof

Abstract

The invention relates to a flame-retardant Mg alloy doped with Gl and Sr and a preparation method thereof. The alloy is made from Mg, Al, Zn, and Mg-Mn intermediate alloy as raw materials, Al-Gl intermediate alloy and Al-Sr intermediate alloy as fire retardants and Al-Sr intermediate alloy as an agent for enhancing mechanical property of the alloy. The preparation method is carried out in a vertical smelting furnace, and comprises smelting at 710 plus or minus 5 DEG C, refining at 760 plus or minus 5 DEG C, standing, casting at 700 plus or minus 5 DEG C, adding smelting and refining agents, incubating at a constant temperature, standing to obtain a molten liquid of flame-retardant Mg alloy, casting in a die, cooling, cutting and shaping to obtain flame-retardant Mg alloy ingot. During the smelting process, the addition of Al-Gl intermediate alloy and Al-Sr intermediate alloy can efficiently prevent the combustion and oxidation of Mg alloy and simultaneously improve the mechanical property of Mg alloy. This method has the advantages of rigor process, reasonable formation, short process flow, less environmental pollution, and good compactness and uniformity of metallurgical structure of Mg alloy ingot product. The average crystal grain of the product is less than or equal to 90 micron, the tensile strength reaches 200 MPa, and the impact ductility reaches 15J / cm<2>.

Description

technical field [0001] The invention relates to a flame-retardant magnesium alloy added with beryllium and strontium and a preparation method thereof, belonging to the technical field of nonferrous metal preparation methods. Background technique [0002] Magnesium alloy is one of the lightest metal materials currently available in industry. It has high specific strength and specific stiffness, good electrical and thermal conductivity, magnetic shielding, damping and shock absorption, and machinability. It is used in automobiles, electronics and Widely used in aerospace field. [0003] The smelting of magnesium alloys is completed in a resistance melting furnace. During the smelting process, oxidative combustion often occurs, which brings technological difficulties to the smelting of magnesium alloys and the casting of products, and the environmental pollution is serious and the product qualification rate is low. [0004] In order to solve the problem of oxidative combustion...

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Problems solved by technology

[0003] The smelting of magnesium alloys is completed in a resistance melting furnace. During the smelting process, oxidative combustion often occurs, which brings technological difficulties to the smelting of magnesium alloys and the casting of products, and the environmental pollution is serious and the product qualification rate is low.

[0004] In order to solve the problem of oxidative combustion of magnesium alloys in the smelting process, flux covering or gas protection methods are generally used, but there are problems of environmental pollution and complex equipment, such as the commonly used sulfur hexafluoride SF 6 Gas is an internationally banned polluting gas, and the flux coverage will cause pollution to the magnesium alloy liquid, which cannot meet the product requirements, and will also cause waste of materials and energy

[0005] Magnesium alloys are easy to oxidize and burn because the magnesium oxide film is loose and not dense, which cannot prevent the contact between air and magnesium. Therefore, adding alloy elements to magnesium alloys to form a dense protective film can also play a role in flame retardancy. Adding rare earths or calcium can also improve the flame retardancy. It is generally used in heat-resistant magnesium alloys, and the calcium element will reduce the mechanical properties of the alloy, while the rare earths can only improve the flame retardancy. Adding beryllium to the magnesium alloy It can also improve flame retardancy, but improper proportion or excessive beryllium will also cause grain coarsening and reduce mechanical properties. The current flame retardancy methods have disadvantages and deficiencies, and are not ideal

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