Aluminum-based composites reinforced with SiC particles and NiTi fibers: influence of fiber dimensions and aging time on mechanical properties

NiTi short fiber and SiC particle reinforced 6061 Al alloy composites have been prepared by pressure-assisted induction heating method in ambient atmosphere. Two different composites with significant difference in NiTi fiber diameter (127 and 51 mu m) have been prepared. It is found that 51-mu m NiTi fibers are better bonded with the Al matrix; de-bonding has seldom been observed. There is better microstructural compatibility, i.e., fiber diameter is of the same order as the Al matrix grain size for this case. However, when 127-mu m NiTi fibers are used, de-bonding and "pull-out" mechanism can be frequently observed. Aging effect on the properties of the composite has also been investigated. TEM and EDS experiments indicate that there is no evidence that the bonding of NiTi/Al is affected by either aging or size of NiTi fiber.