Influence of rotational speed and reinforcements on wear and mechanical properties of aluminum hybrid composites via friction stir processing

In this paper, the effect of reinforcement particles such as Silicon carbide (SiC), Graphite (Gr) and rotational speed on wear and mechanical properties of Aluminum alloy 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 and revealed that the reinforcement particles (i.e. SiC and Gr) are uniformly dispersed in the nugget zone. It is also observed that the microhardness at optimum condition is increased due to the presence and pining effect of hard SiC particles. The wear resistance of the surface hybrid composite is increased due to the mechanically mixed layer generated between the composite pin and steel disk surfaces which contained fractured SiC and Gr. The observed wear and mechanical properties have been correlated with microstructures and worn micrographs.

► Hardness of the surface hybrid composite increased due to the presence and pining effect of SiC particles. ► Wear rate is decreased due to the presence of Gr particles which acted as a solid lubricant. ► Size of the reinforcement particles were reduced to 5 μm after FSP. ► At optimum condition the distribution of reinforcement particles are found to be uniform. ► Good bonding between the reinforcement particles and matrix is observed.