Magnesium-based composite material semi-solid indirect extrusion casting forming method

Abstract

The invention relates to a magnesium-based composite material semi-solid indirect extrusion casting forming method. According to the magnesium-based composite material semi-solid indirect extrusion casting forming method, in order to solve the problems that wettability is poor between reinforcing body particles and matrix material, agglomerate is prone to be generated, distribution is uneven, anda prepared casting is low in performance, magnesium-zinc-yttrium quasi-crystals with high hardness, high elasticity and good binding property with a matrix are added to a magnesium alloy matrix and used as a reinforcing body, the casting is obtained through smelting in a vacuum atmosphere smelting furnace, ultrasonic-assisted vibration stirring in a composite stirring furnace and indirect extrusion casting, and therefore the mechanical property of the casting is improved; the machining method is advanced in process, data are accurate and detailed, the metallographic structure of the casting isgood in compactness, and defects of shrinkage cavity and shrinkage porosity do not exist; and the initial phase in the metallographic structure is composed of spherical and near-spherical grains, dendritic grains basically disappear, the grain size is obviously refined, tensile strength reaches 225 Mpa, the elongation rate is 6.5%, and hardness reaches 86 HV, so that the method is advanced.

Description

technical field [0001] The invention relates to a semi-solid indirect extrusion casting molding method of a magnesium-based composite material, which belongs to the technical field of preparation and application of non-ferrous metal materials. Background technique [0002] Magnesium alloy has excellent characteristics such as light weight, high specific strength and specific stiffness, good thermal and electrical conductivity, damping and vibration reduction, electromagnetic shielding, easy processing and forming and recycling, and is listed as a high-end new material; however, currently commonly used magnesium alloys have low strength. , poor oxidation resistance and poor high-temperature creep resistance limit its further application in industry; therefore, it is necessary to improve the comprehensive performance of magnesium alloys and develop new magnesium-based composite materials; currently, most of them use Al 2 o 3 , SiC, TiC, SiO 2 Particles are added to the magne...

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Problems solved by technology

[0002] Magnesium alloy has excellent characteristics such as light weight, high specific strength and specific stiffness, good thermal conductivity, damping and vibration reduction, electromagnetic shielding, easy processing and recycling, etc., and is listed as a high-end new material; however, currently commonly used magnesium alloys have low strength. , poor oxidation resistance and poor high temperature creep resistance limit its further application in industry; therefore, it is necessary to improve the comprehensive performance of magnesium alloys and develop new magnesium-based composite materials; currently, most of them use Al 2 o 3 , SiC, TiC, SiO 2 Particles are added to the magnesium alloy matrix as a reinforcement to obtain a magnesium-based composite material. However, the wettability between the added particles and the magnesium alloy matrix is ​​poor, and they are prone to agglomeration and uneven distribution in the matrix. At the same time, the added particles and magnesium Interfacial reactions occur in the alloy matrix, generating some harmful brittle phases, thus reducing the performance of the composite material

[0003] Stirring casting is commonly used to prepare magnesium-based composite materials. It is stirred in a liquid state. The negative pressure generated during the stirring process makes the composite material easy to absorb air and form pores. In addition, the density difference between the reinforcing particles and the matrix alloy is easy to cause particle deposition and fine particles. The agglomeration phenomenon, forming the second phase segregation, makes the distribution of reinforcing particles uneven in the matrix; pouring in the liquid state, due to the high molding temperature, it is easy to cause defects such as shrinkage cavity and shrinkage porosity inside the casting after molding, which reduces the casting. mechanical properties

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