SLIDING WEAR BEHAVIOR OF ALUMINUM-BASED METAL-MATRIX COMPOSITES PRODUCED BY A NOVEL LIQUID ROUTE

TiC-reinforced MMCs have been produced in a range of aluminium alloys using a novel casting technique which results in spontaneous incorpora tion of the particles into the melt and thus strong bonding between th e particles and the matrix. The sliding wear behaviour of the extruded composites has been studied as a function of load and particle volume fraction and has been compared with a commercially available SiC-rein forced composite. In all cases, alloy reinforcement resulted in a redu ction in wear rate and an increase in the load at which the transition from low rate wear to high rate wear occurred. In the low rate wear r egime, the wear coefficients of all the alloys in both the reinforced and unreinforced states were similar, and since the TiC-reinforced A35 6 alloy was the hardest (due in part to the grain refining action of T iC), it exhibited the lowest wear rate (lower than that of the SiC-rei nforced composite). Wear of the steel counterface depended on the mech anism of wear of the composite. An increase in load generally resulted in an increase in wear rate of both the composite pin and counterface , and the reasons for this are presented. Increasing the volume fracti on of particles in a composite reduces its wear rate but generally inc reases the wear rate of the counterface. It is suggested that when bot h counterface and composite wear are considered, an optimum volume fra ction of particles exists at which wear is lowest. (C) 1998 Elsevier S cience S.A. All rights reserved.