Friction and wear studies of die cast aluminum alloy-aluminum oxide-reinforced composites

Purpose - Metal matrix composites (MMCs) are engineered materials formed by the combination of metal matrix and reinforcement materials. They have a stiff and hard reinforcing phase in metallic matrix. The matrix includes metals such as aluminum, magnesium, copper and their alloys. The purpose of this paper is to describe the development of an aluminum alloy-aluminum oxide composite using a new combination of vortex method and pressure die casting technique and the subsequent tribological studies. Design/methodology/approach - An aluminum alloy-aluminum oxide composite was developed using vortex method and pressure die casting technique. The aluminum alloy-1 wt% aluminum oxide was die cast using LM24 aluminum alloy as the matrix material and aluminum oxide particles of average particle size of 16 mu m as a reinforcement material. The friction and wear characteristics of the composite were assessed using a pin-on-disc set-up; the test specimen, 8-mm diameter cylindrical specimens of the composite, was mated against hardened En 36 steel disc of 65 HRC. The tests were conducted with normal loads of 9.8, 29.4 and 49 N and sliding speeds of 3, 4 and 5 m/s for a sliding distance of 5,000 m. The frictional load and the wear were measured at regular intervals of sliding distance. Findings - The effects of normal load and sliding speed on tribological properties of the MMC pin on sliding with En 36 steel disc were evaluated. The wear rate increases with normal load and sliding speed. The specific wear rate marginally decreases with normal load. The coefficient of friction decreases with normal load and sliding speed. The wear and friction coefficient of the aluminum alloy-aluminum oxide MMC are lower than the plain aluminum alloy. The wear and coefficient of friction of the entire specimens are lower. Practical implications - The development of aluminum alloy-aluminum oxide composite using vortex method and pressure die casting technique will revolutionize the automobile and other industries, since a near net shape at low cost and very good mechanical properties are obtained. Originality/value - There are few papers available on the development of (or tribological studies of) MMCs including aluminium/aluminium alloy-ceramic composites developed by combination of vortex method and pressure die casting technique.