SELF-LUBRICATING ALUMINUM METAL-MATRIX COMPOSITES DISPERSED WITH TUNGSTEN DISULFIDE AND SILICON-CARBIDE

This paper describes the synthesis and tribological behavior of self-lubricating aluminum alloy metal-matrix composites (MMCs). The formulations of MMCs comprised of tungsten disulfide (WS2) and silicon carbide (SiC) particles dispersed in a commercial aluminum alloy (Al-0.40Si-0.75Mg) matrix. Composites were fabricated by a conventional powder metallurgy route involving blending, compacting and sintering. Friction and wear tests (up to a duration of one million cycles) were performed in a ball-on-disk configuration against a steel counterface. Wear scars on MMC disks and steel balls were analyzed in SEMIEDXS. In a dry nitrogen environment, the steady state friction coefficient of an Al-0.10SiC-0.03WS2MMC was 0.05, whereas in laboratory air (with relative humidity at approximately 65 percent it was 0.10. In both environments, transfer of aluminum to the steel counterface was absent.