A particle-mixed aluminum-based self-lubricating composite material and its preparation method

Abstract

The invention discloses a particle-mixed aluminum-based self-lubricating composite material and a preparation method thereof. In terms of preparation, the combination of semi-solid stirring casting and high cooling rate directional solidification is used to overcome the macroscopic inhomogeneity of particle distribution caused by the difference in density between the added particles and the matrix metal through semi-solid stirring casting, and through high cooling rate directional solidification The method alleviates the inhomogeneous distribution of grain boundaries and grains in the matrix metal caused by the difference in particle wettability. In terms of component design, graphite (lower density, poor wettability) and cermet particles Ti3SiC2 (density Larger, better wettability) two kinds of particles, which are differentiated in density and wettability from the configuration of the matrix metal, further reducing the macroscopic and microscopic inhomogeneity of the particle distribution. The prepared self-lubricating composite material has good strength, high wear resistance and good plasticity, and can realize hot forming. The preparation method of the invention is simple, easy to operate and easy to control the process.

Description

technical field [0001] The invention relates to a self-lubricating composite material and a preparation method thereof, in particular to an aluminum-based self-lubricating composite material mixed with titanium carbide silicide particles and graphite powder particles and a preparation method thereof. Background technique [0002] Self-lubricating materials are divided into three categories: polymer-based, ceramic-based and metal-based. Metal-based self-lubricating composite materials have both the characteristics of metal substrates and the tribological characteristics of solid lubricants, and are suitable for use in atmospheric environments, chemical environments, electrical environments and The use under various conditions such as high temperature and high vacuum has become a hot spot in research and development in the field of material science. [0003] In the 1970s, people added solid lubricants to refractory metals such as tungsten, molybdenum, chromium, and niobium to ...

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Problems solved by technology

[0003] In the 1970s, people added solid lubricants to refractory metals such as tungsten, molybdenum, chromium, and niobium to prepare refractory metal-based self-lubricating composite materials. They are widely used in high-temperature, high-speed, and high-friction and heat-generating environments, but they are expensive. , complex molding, difficult sintering, and gradually replaced by iron-based and copper-based materials; iron-based self-lubricating composite materials have high matrix hardness, but poor corrosion resistance, easy to produce diffuse hard points, easy to produce large dual parts such as shafts damage; copper-based self-lubricating composite materials have high comprehensive performance, but poor compliance and embedding, and relatively high cost; silver-based self-lubricating composite materials have great advantages in the electronic field, nickel-based high-temperature self-lubricating composite materials Lubricating composite materials are mainly used in high temperature fields, but the cost is high

The wettability between graphite and metal melt is poor, and the cooling rate that is swallowed or captured by aluminum melt is difficult to achieve, resulting in a large amount of agglomeration at the grain boundary and resulting in microstructure segregation

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