High-speed tribological properties of some Al/SiCp composites:: I.: Frictional and wear-rate characteristics

The friction and wear behaviour of four Al/SiCp composites has been investigated over a wide range of sliding conditions by the use of a specially adapted high-speed tester of the pin-on-disk configuration. Two of the composites tested were fabricated in-house by a powder metallurgy route incorporating mechanical alloying; two commercially sourced composites were also tested far comparison. Generally, wear rate increased with increasing load, but it varied in a rather complex manner with speed depending on which regime the sliding condition fell into. Three regimes of tribological behaviour, demarcated by sliding speed, were observed for these composites. In Regime I, lower rates of wear are observed while in Regime II, catastrophic failures occur when a certain critical load is exceeded, resulting in the rapid adhesion of a large amount of specimen material to the counterface: it is no longer possible to continue with the test when this happens. In Regime III, extensive melting of the composites takes place, and under such a sliding condition, the size of reinforcement particles appears to have an important influence on the rate of wear of these composites. (C) 1999 Elsevier Science Ltd. All rights reserved.