Influence of reinforcements (SiC and Al2O3) and rotational speed on wear and mechanical properties of aluminum alloy 6061-T6 based surface hybrid composites produced via friction stir processing

• Hardness of surface hybrid composite was increased.
• Wear rate is immensely decreased at optimum condition.
• Size of reinforcements was reduced to 5 μm after Friction stir processing.
• Good bonding between the SiC reinforcement particles and Al matrix is observed.
• Micro voids are observed between the Al2O3 reinforcement particles and Al matrix.

In this investigation, the influence of rotational speed and reinforcement particles such as silicon carbide (SiC), alumina (Al2O3) on wear and mechanical properties of aluminum alloy based surface hybrid composites fabricated via friction stir processing (FSP) was studied. Taguchi method was employed to optimize the rotational speed and volume percentage of reinforcement particles for improving the wear and mechanical properties of surface hybrid composites. 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 and Al2O3) are uniformly dispersed in the nugget zone. It also revealed that the microhardness at optimum condition is increased due to presence and pining effect of hard SiC and Al2O3 particles. It is found that the reinforcement particles (i.e. SiC and Al2O3) reduced in size (∼5 μm) than the as received particles size and also observed that the wear resistance at optimum condition is immensely improved. The observed wear and mechanical properties have been correlated with microstructures and worn micrographs.