Study On Preparation And Properties Of SiC_p/Cu Gradient Composites

SiCp/Cu gradient composites was fabricated by powder metallurgy. The microstructure, hardness and conductivity of SiCp/Cu gradient composites were investigated by optical microscope, scanning electronical microscope, XRD and eddy current conductivity instrument. The thermal fatigue properties, oxidation properties and wear resistance were discussed in this paper. The results are as follows.The matrix of SiCp/Cu gradient composites is continuous, there is no interface between layers, and the distribution law of reinforced particles is gradient. The average density of SiCp/Cu gradient composites is enhanced 7.1% and conductivity is increased 7.8% by re-pressing and re-sintering process. After the compression deformation, the maximum density reached 96.1%. The conductivity of SiCp / Cu composite decreased with the increase of SiC content, and the conductivity increased by compressive deformation and annealing. The hardness of a gradual increase in the conductivity decreased gradually from the matrix to the surface of SiCp/Cu gradient composites. SiCp/Cu gradient composites is repeatedly tested by water quenching with the temperature difference of 600℃, and the results show that six-layered and higher than six-layered SiCp/Cu gradient composites have no crack between layers after 80 cycle water quenching, and have the better thermal fatigue resistance properties.The oxidation experiments show that the oxidation resistance behavior of SiCp/Cu composites is better than Cu between 400℃and 700℃. 20%vol SiCp/Cu composites and with SiC 20μm in size has the better oxidation resistance behavior. With the oxidation time added, the mass gained of the composites added, and showed the same changes in the law of parabola in the cyclic oxidation conditions in 700℃;The oxidation resistance properties of SiCp/Cu gradient composites possess the gradient characteristic along the direction of thickness.The wear resistance properties of SiCp/Cu composites are increasing with the SiC content increasing. The wear resistance of SiCp/Cu gradient composites is superior pure Cu, and the distribution law of wear resistance is gradient.When the applied load is lower, the wear mechanism of SiCp/Cu composites is mainly abrasive wear. When the load is higher, the mainly wear mechanism are abrasive wear and delaminating wear of the combination.