Experimental analysis and mechanical characterization of Al 6061/alumina/bagasse ash hybrid reinforced metal matrix composite using vacuum-assisted stir casting method

Abstract

This experimental analysis aimed to fabricate low cost, lightweight metal matrix composite using Al 6061 as matrix material and alumina (Al₂O₃) and bagasse ash as reinforcing material through stir casting process. In this process one cast of single reinforced composite (Al 6061/5 wt% Al₂O₃) and three casts of hybrid reinforced composite (Al 6061/5 wt% Al₂O₃/ 4, 6, 8 wt% bagasse ash) were developed and processed as per ASTM standards followed by mechanical (micro-hardness, ductility, compression, tensile, and impact strength), physical (density and porosity), and microstructure (optical and SEM microscopy) characterization. The mechanical properties such as tensile strength, hardness, and compressive strength showed good improvements in the manufactured hybrid reinforced metal matrix composite (HRMMC) in comparison with the single reinforced metal matrix composite (SRMMC). The tensile strength and hardness of developed composite increased continuously with an increase in bagasse ash contents up to 6 wt% having maximum increment of 9.09% (tensile) and 16.5% (hardness) and thereafter both decreased for 8 wt% of bagasse ash, respectively. The results of impact strength and ductility of Al 6061/Al₂O₃/bagasse ash showed marginal reduction, as the wt% of reinforcements increased. It was found that the density of HRMMC was less than the SRMMC and it decreased with increasing wt% of reinforcements however, the composite contained some porosity percentage (max. value 2.26%), which increased as the wt% of reinforcement increased. The microstructure analysis showed fair distribution with good interface bonding up to 6 wt% bagasse ash.