Study On Preparation Of Copper Matrix Composites Enhanced By Molybdenum Silicide And Friction And Wear Properties

The rapid developments of electronic, mechanical, aeronautic and aerospace industries have promoted an imperative demand of developing functional materials with high electrical conductivity, thermal conductivity, wear resistance and mechanical properties, while the fabrication cost is lower. The applications of such functional materials may improve the working continuity while reduce the direct or indirect losses induced by frequent replacement of components. However, there are some limitations exist in the current commercial copper alloys, such as the low wear resistance due to the lack of load-bearing particles, the loss of dispersion strengthen effects under high-temperature conditions. Therefore, copper alloys have shown unfitness in the ever-increasingly rigorous application environments. Particle reinforced copper matrix composites can keep the high electrical and thermal conductivity of copper, and possess high mechanical properties, good wear resistance. Consequently, it is hopeful to develop new kinds of functional materials with high conductivity and wear resistance, by systematic researching on particle reinforced copper matrix composites.Particle reinforced copper matrix composites were prepared by in-situ process and reaction sintering. The microstructure, mechanical and dry sliding wear behavior was investigated; mostly task as follows:The thermo dynamic data or the reactions between Mo and Si in the molten liquid of copper were analyzed. The copper matrix composites were prepared by reactions of Mo, Si and Cu by in-situ composites; the copper alloy has been prepared by infiltration sintering, the paper analyzed the effect of sintering temperature, different content on organizations of copper alloy.The microstructure and mechanical of the in -situ composites were investigated by using optics microscope, EDS and XRD. The results showed that the in-situ formed Mo₃Si particles which exhibited a homogenous dispersion in the copper matrix. Moreover, by the presence of oxygen under the experimental conditions, and participate in the reaction of SiO₂. Under this experimental condition, enhancement MoSi₂ decomposes into the Mo₅Si₃ pellet, Accompanied by a small number of SiO₂, irregular in shape, size, clear interface; lower casts infiltrates temperature and the lower MoSi₂ content is advantageous to tiny of the MoSi₂ dispersion-strengthened copper alloy. In higher casts infiltrates the temperature, the enhancement pellet grows up, the tendency is serious.Particles can be enhanced by adding well improve the mechanical properties of the substrate, the substrate Mo₅Si₃ particles on the enhancement of a good role in enhancing the hardness of composite materials. Infiltration high temperature materials to lower density than the high temperature, high temperature can increase the material's density.Dry sliding wear behavior of CU-Mo₅Si₃ composites were investigated using a pin-on-disk test rig. It has been found that as Mo₅Si₃ enhanced greatly improved by adding particles of the composite material hardness and wear resistance, and with the increase of the content, the coefficient of friction and wear reducing. As the load increases, composite materials to reduce the friction coefficient, and the wear is mainly adhesive wear, the high temperature in the circumstances, the addition of Mo₅Si₃ enhanced particles can effectively prevent matrix softened, and tend to reduce the adhesive, the wear resistance of a good performance.