Comparison of effect of SiC and MoS2 on wear behavior of Al matrix composites

In order to improve dry sliding wear resistance of pure aluminum against steel, aluminum-based composites reinforced with different contents of SiC, MoS2 and SiC/MoS2 particles were synthesized by press and sintering of the corresponding powder mixtures. The microstructural evaluations showed a dense microstructure which were in good agreement with the result of density and hardness measurements. The results of pin on disk wear tests performed against an AISI 52100 steel pin at a constant load and sliding velocity showed that there was a critical content for both types of the reinforcements at which the lowest wear rate was obtained, i.e. 10 vol.% and 2 vol.%, respectively, for Al/SiC and Al/MoS2 composites. However, the lowest wear rate and friction of coefficient were attained for Al/10SiC/2MoS(2) hybrid composite. According to the scanning electron microscope observations, the predominant wear mechanism was changed from adhesion to abrasion mostly when MoS2 particles were incorporated in the pure aluminum. Mild delamination was identified as the main wear mechanism for Al/SiC and Al/SiC/MoS2 composites. The frictional traces and worn surfaces of Al/SiC/MoS2 composites approached to those of Al/SiC composites, indicating the dominant role of SiC particles in tribological behavior of the hybrid composites.