Dry tribological behaviour of microwave-assisted sintered AA2024 matrix hybrid composites reinforced by TiC/B4C/nano-graphite particles

Abstract This study aimed to produce hybrid composites with a AA2024 matrix reinforced by TiC/B4C/nano-graphite through a microwave-assisted sintering technique at 560 °C for 60 min. The nano-graphite ratio in the produced composite samples was kept constant as 1 wt%. TiC and B4C were used in equal ratios at 2, 6 and 10 % by weight total to determine their effects on tribological properties. Wear tests were conducted under three different loads: 3, 5 and 10 N. In the hybrid composites produced, an inverse correlation was observed between the increase in reinforcement ratio and sinterability, while a direct correlation relationship was found in hardness and wear resistance. Compared to the sample containing 2 % TiC/B4C in total by weight, a ∼50 % increase in Brinell hardness and a 52–68 % decrease in wear rate was obtained in the sample containing 10 % TiC/B4C. As the reinforcement ratio increased, tribofilm formation increased, and abrasive wear was replaced by mild-oxidative wear type.