SiCp/Al MMC Bearing Liners

DWA Aluminum Composites proposes the use of powder-metallurgy based, silicon carbide particulate (SiCp) reinforced aluminum Metal-Matrix-Composites (MMCs) for the replacement of 4320 steel alloy bearing liners to achieve weight reduction in the gearboxes of the CH-53K helicopter. Ceramic particulate reinforced aluminum MMCs possess the properties of interest to the Navy, including 1) density on par with monolithic aluminum alloys, 2) increased tensile and compressive strength, 3) increased tensile and compressive modulus, 4) improved wear resistance, and 5) gearbox environmental compatibility. The Phase I program will concentrate on mechanical and wear screening tests for conventionally sized SiCp reinforcement and"ultra-fine"SiCp reinforcement in moderate and high strength alloys in simple extrusions. The primary questions the Phase I program will seek to answer are 1) what are the effects of SiCp size and matrix alloy composition on strength and wear properties and 2) are the strength and wear properties obtained sufficient for application to bearing liners. If the Phase I program is successful, it will help to establish lightweight MMC bearing liners with 1/3 the density of 4320 steel that can be mass produced using conventional thermo-mechanical processing of ring structures over a broad range of diameters, large and small.