Abstract: The effects of aging and whisker-orientation on the wear behavior of SiC_w/Al composites under unlubricated sliding friction were investigated.The surface profiles of GCr 15 rings against different aging treated MMC samples were also studied.The results show that the whisker orientation in the as-extruded SiC_w/Al composite exerts a significant influence on the wear resistance;the lowest wear rate was observed on the specimen in which the axis of SiC_w is normal to the wear surface.Proper over-aging provides the best wear resistance and results in milder damage to the counter ring due to less departure and fracture of SiC whiskers.