Tribological Behavior of Cu Matrix Composites Containing Graphite and Tungsten Disulfide

Copper matrix composites containing graphite and tungsten disulfide were prepared and tested under the loads of 1-5 N to investigate their friction and wear behaviors. The microstructure, worn surfaces, and cross section of worn subsurfaces were observed, and the lubricating films formed on the worn surfaces were analyzed. It is found that the Cu-24 vol% WS2 composite presents a higher mechanical performance and lower wear rate compared to the Cu-24 vol% graphite composite with same volume fraction of solid lubricant. This could be attributed to the high-strength chemical bonding of the interface between WS2 and the copper matrix. The high-strength interfacial bonding also helps prevent plastic deformation and the formation of cracks at the worn subsurfaces of the composites. The amount of lubricant on the outmost worn surfaces is significantly higher than that in the composite. The lubricating film of WS2 with relatively high thickness provides a low friction coefficient to the composites.