Wear properties of hybrid ABO+BN+CNT/Al-Sn alloy matrix composites for engine bearing materials

Abstract

Engine bearing materials need improved wear resistance to withstand high speeds and heavy loads. To meet the requirements of bearing materials, a new metal matrix composite (MMC) was designed. Here, the hybrid aluminum borate whisker (Al18B4O33, ABO) + hexagonal boron nitride (BN) + carbon nanotubes (CNTs)/Al-5Sn alloy MMCs were fabricated by squeeze infiltration. The wear properties of the hybrid MMCs were evaluated using a ball-on-disk tester. The effect of hybridization of ABO, BN, and CNTs on the wear properties of the Al-Sn MMCs was investigated. The microstructure of the hybrid MMCs showed a uniform distribution of the reinforcements. The wear resistance of the Al-5Sn alloy improved with the addition of ABO. The wear properties of the ABO+BN/ Al-Sn and ABO+CNT/Al-Sn MMCs were considerably enhanced compared to those of the ABO reinforced Al-Sn MMC because of the lubricating characteristic of BN and CNTs, and the CNTs were more effective than BN. The friction coefficient and wear rate of 20ABO+5BN+5CNT/Al-Sn MMC decreased by 1/4 and 1/20, respectively, compared to that of the ABO/Al-Sn MMC.