Friction and wear of 20% volume fraction submicron aluminum oxide/6061 aluminum alloy composite for brake system application

Metal matrix composites (MMCs) containing hard particulates offer superior operating performance and resistance to wear. The strengthening of aluminum alloys with a dispersion of fine ceramic particulates has dramatically increased their potential for wear resistance applications. One of these applications is the development of aluminum matrix composite (AMC) brake discs, favored primarily over cast iron for their high thermal conductivity and low density. Consequently, these materials tend to be lighter in weight and harder than the traditional cast iron brake discs. Therefore they offer potential for reducing braking system weight, improving the friction coefficient and possibly increasing the wear life of brake components as well. Friction and wear performance are the most important considerations in the design of MMC brake discs, and it is the investigation of the interdependence of these two properties that comprise the bulk of this work.;There have been studies which concentrated on the investigation of wear behavior of SiC particulate reinforced aluminum alloys for disc brakes. However, no published data have been found which aimed to delineate the tribological performance of submicron Al2O3 reinforced aluminum alloys. The prime objective of this work is to evaluate the friction and wear characteristics of 20% volume fraction sub-micron Al2O 3 reinforced 6061 Al composite as a brake counter face. These characteristics are evaluated at varying loads and sliding speeds at room temperature in dry sliding conditions. The results are compared with gray cast iron under similar conditions. The average wear rate of AA6061/Al2O3/20p composite is found to be 18% lower than that of gray cast iron sliding against semi-metallic brake pad material. The average wear rate for brake pad material is found to be 31% lower while sliding against AA6061/Al2O 3/20p composite than sliding against gray cast iron. The proposed aluminum composite is found to be a better candidate for brake rotor applications.