Effects of reinforcements on sliding wear behavior of aluminum matrix composites

Effects of reinforcements on the wear behavior of aluminum matrix composites were investigated by pin-on-disk tests. The matrix materials were 2024 and ADC12 aluminum alloys. The volume fractions of SiC whiskers (Vfw) were 5–29% (MMCw), Al2O3 fibers (Vff) were 3–26% (MMCf), and SiC particles (Vfp) were 2–10% (MMCp). The MMCs were rubbed against a carbon steel pin under a load of 10 N at a sliding velocity of 0.1 m s−1. The degree of improvement in dry sliding wear resistance brought about by reinforcement is strongly dependent on the kind of reinforcement as well as its volume fraction (Vf). Initial severe wear did not occur for MMCs with Vfp=5%, Vff=10% and Vfw=22%. The Vf at which the steady-state wear rate decreased to the minimum value was 2, 10 and 29% for MMCp, MMCf and MMCw, respectively. For MMCf, however, the wear rate increased above a certain value of Vff. Fiber and particle fragments were large in size and angular in shape, so that they promoted abrasion on the steel counterface. The aggressive action on the counterface increased in the order MMCw, MMCp and MMCf. By summarizing our results and those in the literature, we conclude that particle reinforcements are the most effective in improving the wear resistance of MMC.