Al7075 / Ti ₃ AlC ₂ MAX-phase surface composite generated by friction stir processing: Microstructure, microhardness, and tribological characteristics

Aluminium 7075 alloys has a wide range of applications in the aerospace sector because of its good strength as compared to other Al alloys. Nevertheless, the life of 7075 alloys are limited due to its poor tribological properties. In this study, investigations were conducted into the effects of Ti 3 AlC 2 particles and friction stir processing (FSP) on the microstructure, microhardness and tribology of Al 7075. The microstructure observations revealed significant grain refinement was seen in both the base metal and the aluminum-Ti 3 AlC 2 composites. The area mapping revealed that the Ti 3 AlC 2 particles were uniformly dispersed across the friction stir processed zone. The microhardness of the base metal, base metal friction stir processed and Al-Ti 3 AlC 2 were 100 HV 0.2 , 180 HV 0.2 and 350 HV 0.2 . The reason for increase in microhardness is mostly due to grain refinement. The microstructure evolution also led to improvement in wear resistance which is approximately 5 times than the parent metal. Scanning electron microscopy micrographs revealed that abrasive wear with variable degrees and characteristics was the main wear mechanism.