Tribological properties of SiC whisker and molybdenum particle-reinforced aluminum matrix composites under lubrication

Composite specimens of 2024 aluminum alloy reinforced with 15 vol.% SiC whiskers and 15 vol.% molybdenum powder were fabricated using powder metallurgy (PM). The composite pins were run against a 440C disk in a Falex-6 multi specimen friction and wear testing machine. Paraffin oil containing 3 wt.% tricresyl phosphate (TCP), chlorinated paraffin (CP) or zinc dialkyldithiophosphate (ZDDP) additives was used to lubricate the composites. The composites exhibited good friction- and wear-resistance properties at loads less than 600 N (34.3 MPa) and a rotational velocity of 606 rev min(-1) (tangential velocity of 0.75 m s(-1)). Under these conditions, the main wear mechanism is tribochemical wear. With increasing load, the wear rate increases quickly and the wear mechanism is plowing with delamination.