Mechanical and Microstructural Characteristics of Aluminium 6063 Alloy/Palm Kernel Shell Composites for Lightweight Applications

Abstract The mechanical properties and microstructure of AA6063 alloy reinforced with palm kernel shell (PKS) powder were studied. AA6063 matrix composites reinforced with varying weight fractions of palm kernel shell particles (ranging from 2.5% to 15% at 2.5 intervals) were prepared using the stir compocasting technique. The mechanical properties and microstructure of the developed composites were analysed and compared with the matrix alloy. The experimental results showed that palm kernel shell reinforcement influenced the structure of AA6063 alloy through grain refinement as it remained homogeneously dispersed within the matrix, and the mechanical properties of the composites were improved. The mechanical stirring action employed during composite fabrication was an effective factor that influenced the enhancement of the mechanical properties of AA6063-PKS matrix composites. AA6063-PKS composites had improved mechanical properties compared to AA6063 alloys without reinforcement. The mechanical properties increase with increasing weight fraction of PKS particle in terms of the ultimate tensile strength (78.93% at 7.5%pks), yield strength (98.82% at 7.5%pks), %elongation (32.2% at 12.5%pks), and impact strength (12.92j to 31.96j at 10%pks), while hardness decreases with increasing content of PKS particle (from 2.5%-15%pks), but maintained values higher than that of the unreinforced base alloy. This progressive decrease in hardness as the reinforcement increases was due to agglomeration and non-homogeneity at higher reinforcement volume.