Wear and mechanical properties of 6061-T6 aluminum alloy surface hybrid composites [(SiC + Gr) and (SiC + Al2O3)] fabricated by friction stir processing

In this investigation, the influence of tool rotational speed on wear and mechanical properties of aluminum alloy based surface hybrid composites fabricated via Friction stir processing (FSP) was studied. The fabricated surface hybrid composites have been examined by optical microscope for dispersion of reinforcement particles. Microstructures of all the surface hybrid composites revealed that the reinforcement particles (SiC, Gr and Al2O3) are uniformly dispersed in the nugget zone. It was observed that the microhardness decreases when increasing the rotational speed and showed higher microhardness value in Al–SiC/Al2O3 surface hybrid composite due to presence and pining effect of hard SiC and Al2O3 particles. It was also observed that high wear resistance exhibited in the Al–SiC/Gr surface hybrid composites due to presence of SiC and Gr acted as load bearing elements and solid lubricant respectively. The observed wear and mechanical properties have been correlated with microstructures and worn micrographs.