MECHANICAL AND WEAR PERFORMANCE OF END CHILLED ALUMINIUM -2024 MATRIX COMPOSITES REINFORCED WITH AL2O3 NANO PARTICLES

In recent years, the use of lightweight materials with improved mechanical and tribological qualities has significantly advanced. This study aims to develop an aluminum 2024 matrix alloy reinforced with 0, 3, 6, 9, and 12 weight percent of Al2O3 using the stir casting technique. The alloy was melted at approximately 700°C, mixed with preheated Al2O3 particles, and cast into a sand mold with various end chills, including graphite, mild steel, copper, brass, and cast iron, to facilitate directional solidification. Mechanical testing revealed that the copper-chilled MMC achieved the highest hardness and strength at reinforcement levels of 9% and 12% by weight, respectively, with increases of 9.88% in strength and 16.66% in hardness compared to the base alloy. Micro structural examination showed uniform dispersion of nano alumina particles, contributing to improved wear resistance. The copper-chilled MMC exhibited high friction and modest wear at lower stresses but significant wear under higher loads. The incorporation of Al2O3 nanoparticles and the chilling effect enhanced the mechanical and tribological properties, resulting in a finer microstructure and better bonding between the reinforcement and matrix.