Journal of Materials Science, Vol.42, No.12, 4149-4158, 2007
Reaction sintering of intermetallic-reinforced composite materials
The goal of this research was to explore the powder metallurgy (P/M) processing response of materials based on the Al-Ni system. In doing so, compacts of pure aluminum powder as well as binary Al-Ni blends were prepared, compacted, sintered, and assessed. Research began with fundamental studies on the sintering response of the base aluminum powder. This system demonstrated a poor sintering response overall but did improve at higher temperatures commensurate with a small fraction of a secondary phase that was presumed to be aluminum nitride. In Al-Ni systems sintering temperature had a particularly pronounced effect on the resultant microstructure. At lower temperatures a composite of Al-NiAb-AlN was formed while higher temperatures yielded one of Al-NiAl3 alone. It was postulated that the exothermicity of NiAl3 formation and the extent of matrix sintering were controlling factors for this behaviour.