Wear Characteristics of NiTi/Al6061 Short Fiber Metal Matrix Composite Reinforced With SiC Particulates

Abstract

Wear characteristics of Al6061 composites, reinforced with short NiTi fibers, were investigated. The NiTi/Al6061 composite samples were fabricated using pressure-assisted sintering process in ambient air where the NiTi fibers are aligned unidirectional in the Al matrix. In addition, NiTi/Al6061 composite with 5 wt % SiC particulates and monolithic Al6061 and Al6061 with 5 wt % SiC particulates were processed in similar conditions. The wear tests were performed using a reciprocating tribometer in ball-on-flat configuration where the counterbody material was martensitic steel. The effects of fiber isotropy and SiC reinforcements on wear resistance were experimentally investigated in dry sliding. Wear properties of the samples were studied using an optical profiler and a scanning electron microscope analysis. The results showed that transverse NiTi fibers improve the wear resistance significantly. Samples with transverse fiber orientation show mostly abrasive wear, whereas, monolithic and parallel samples show adhesive wear mechanism. In addition, SiC reinforcements improve the wear resistance of the composite and the monolithic samples. Since the Al6061 matrix material is smeared onto NiTi fibers in a short period, all composite samples show similar frictional characteristics after certain period of running in dry sliding.