Cu–FeS composites without lead were prepared by power metallurgy process. The friction and wear properties were examined on a “block-on-ring” testing machine under dry sliding conditions with and without oil immersion. Results showed that both the frictional coefficient and the wear volumes decreased with increased FeS content in the composite under dry sliding conditions. In the condition of dry friction without oil immersion, the FeS solid lubricating film formed and played a role of antifriction and adhesion resistance. Under the dry friction condition with oil immersion, the lubricant oil stored in the porous FeS layer precipitated to the surface to form the oil film, which could work together to achieve a liquid–solid synergistic lubrication with the FeS transfer film. The lubrication performance of the collaborative lubrication reaction is better than that of the solid transfer film. With the increase of FeS, the collaborative lubrication became more obvious.

The friction and wear behaviors of reciprocatingly extruded AA 6061–SiC composites form the focal point of this study. To find the optimum way for refining the grains of the matrix, reciprocating extrusion (RE), as a deformation processes, is conducted and found to be feasible. Accordingly, RE has been applied on SiC particles reinforced AA 6061 matrix composite. Using the RE passes as a base, wear behaviors of the composites have been investigated at ambient temperature under dry and lubricated forms. Optical microscopy, transmission electron microscopy and scanning electron microscopy techniques were used to reveal the effect of the RE passes on the microstructure of the materials. As a result, it is found that there is a clear relationship between the weight loss, wear resistance and hardness of the samples. As the load and the number of passes increase, the weight loss in the samples increases. The worn surfaces of the reinforced composites have commonly adhesive and abrasive type of wear.