(503c) In-Situ Densification of Combustion Synthesized Nickel Aluminide-Carbon Nanotube Composites from Nanoreactants

In this study, simultaneous combustion synthesis and densification has been investigated as a unique processing technique for the formation of carbon-nanotube reinforced nickel aluminide. It has previously been demonstrated by our research group that carbon nanotubes survive the short exposure to the high reaction temperature generated by the combustion process. In this work nano sized reactants were utilized to form NiAl-CNT composites with densities up to 96% of the theoretical and nanosized grains are observed. For composites synthesized with 1-wt% SWNTs a 30 % improvement in Vickers microhardness has been observed over the monolithic NiAl material. It is demonstrated that with increased carbon nanotube loading there is a decrease in the composite density, which results in decreased hardness values. The effect of CNT addition on the product morphology, phase composition, and mechanical properties of the composites will be discussed.