A kind of semi-solid indirect extrusion casting molding method of magnesium matrix composite material

Abstract

The invention relates to a semi-solid indirect extrusion casting molding method for magnesium-based composite materials, which is aimed at the problems of poor wettability between reinforcement particles and matrix materials, easy agglomeration, uneven distribution, and low performance of castings produced. Magnesium alloy matrix is ​​added with high hardness, high modulus of elasticity, and good bonding performance with the matrix of magnesium-zinc-yttrium quasicrystal as a reinforcement, which is smelted in a vacuum atmosphere melting furnace, ultrasonic-assisted vibration stirring in a compound stirring furnace, and indirect extrusion casting. The castings are obtained to improve the mechanical properties of the castings; this preparation method is advanced, the data is accurate and detailed, the metallographic structure of the castings is good, there is no shrinkage cavity, shrinkage porosity defects, and the primary phase in the metallographic structure consists of spherical and nearly spherical grains Composition, the dendritic grains basically disappear, the grain size is obviously refined, the tensile strength reaches 225Mpa, the elongation rate reaches 6.5%, and the hardness reaches 86HV. It is an advanced semi-solid indirect extrusion casting method for magnesium-based composite materials.

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...

AI Technical Summary

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

Images