Studies On Preparation And Tribological Properties Of SiC Particules Reinforced Aluminum Matrix Composites

Since their outstanding properties of conductivity, thermal conductivity, antifriction, wear resistance and low thermal distensibility, SiC_p/Al composites are paid more and more attention by the industry. The bonding of matrix and SiC particles is very important to the preparation of SiC particles reinforced Al-alloy-matrix composites which have good performances. In this thesis, SiC particles reinforced Al-alloy-matrix composites were prepared by powder metallurgy technology;and their density, rigidity, tribological behavior and conductivity were studied. The main results show:(1) More compact composites can be prepared with the powder metallurgy technology. With the increasing of the volume of SiC particles the compactness of composites decreased.(2) The hardness of the composites increases with the increase of the volume of SiC particles at first, then the hardness decreases with the further increase of the SiC particles.Under the condition of the same volume of SiC particles, the smaller the powder particules are, the harder the composites are. After the heat treatment, the hardness of the composites increases twice, which suggests the deposition strengthening.(3) The aluminum alloy has a poor wear resistance, but the SiC particles reinforced Al-alloy-matrix composites exhibit an excellent wear resistance. The wear rate of the composites decreases firstly then become stable when the sliding distance increases. The most important factor that influences wear resistance of the composites is the hardness.(4) The dominant wear mechanism of the aluminum alloy is plastic deformation ,but the dominant mechanism of the composites is mainly adhesion and slight scuffing in some extent. With the increase of the volume of SiC particles the slight scuffing takes mre important role, which results in the higher wear resistance of the composites.(5) The conductivity of the composites decreases because of the addition of the SiC particules ,but their conductivity still remains very good. Under the condition of the same size of the SiC particules, the electric resistivity of the composites increases with the increase of the volume of the SiC particules. When the volume of the SiC particules is fixed, the resistivity of the composites decreases with the increase of the seizes of the SiC particules.