Mechanical and metallurgical characterization of B4C and SiC reinforced stir casted AA6061 hybrid MMC

Abstract

The present work was the novel investigation of mechanical and metallurgical characteristics of stir casted AA6061 based metal matrix composites (MMC) and hybrid MMCs. The reinforcements utilized in the investigation were silicon carbide and boron carbide. The thirteen stir casted MMC and hybrid MMC samples were tested for ultimate tensile strength, microhardness, fractography and wear performance. The stir casting process had enhanced the reinforcement distribution within the aluminium matrix. The enhancement in ultimate tensile strength was observed due to the addition of reinforcements in increasing weight percentages with the hybrid MMC exhibiting peak ultimate strength which was a 32.17% improvement against the non-reinforced AA6061 alloy. The formation of reinforcement particulates had enhanced microhardness of the specimens with the peak microhardness observed for boron carbide reinforced MMC exhibiting microhardness 25.41% higher than the base alloy. The hybrid MMC exhibited ductile fracture with highest elongation corresponding to the highest ultimate tensile strength. The wear performance analysis revealed reduced wear rates for the particulate reinforced specimen with highest weight percentage of reinforcements.