Hardness and Wear Behavior of Al7075/TiC/MoS2 Surface Hybrid Composite Produced by Friction Stir Processing

In this study, surface hybrid composites reinforced with TiC and MoS2 were fabricated on heat treated aluminum 7075 substrate via friction stir processing (FSP). For this purpose, reinforcement particles were added to the aluminum 7075 matrix using groove technique, afterward friction stir process was applied using three passes. To evaluate the wear behavior of fabricated composites, reciprocating wear test was applied. Scanning electron microscopy (SEM) was utilized to study wear track and wear particles in order to determine the dominant wear mechanism. The effect of friction stir process on hardness and tribological behavior of aluminum 7075 alloy was studied. The results showed that because of the existence of MoS2 reinforcement particles as solid lubricant, wear resistance of Al7075/TiC/MoS2 surface hybrid composite was significantly improved in comparison with Al/TiC composite samples. It was concluded that abrasive wear mechanism was the dominant mechanism in Al7075/TiC surface hybrid composites. The highest hardness was observed in Al7075/TiC surface hybrid composite, which may be due to the lower hardness of MoS2 particles as solid lubricant in Al7075/TiC/MoS2 surface hybrid composites.