Processing and microstructure development of titanium carbide-nickel aluminide composites prepared by melt infiltration/sintering (MIS)

A combined melt-infiltration/sintering (MIS) route has been described for the preparation of composites that are based on titanium carbide (TiC) with a ductile nickel aluminide (Ni3Al) "binder" phase, This approach allows control of the Ni3Al content, which ran be varied readily in the range of 4-25 vol%. Densities of >98% of the theoretical density have been obtained for composites that have been prepared with Ni3Al contents of greater than or equal to8 vol%, Preliminary examination indicates that the infiltration kinetics approximate to parabolic at 1300 degreesC. Compositional analysis of the densified materials indicates only minimal titanium dissolution into the Ni3Al alloy (<6 at. %), with an analyzed carbide composition of TiC0.93. Cubic grain-growth kinetics are observed for TiC-16-vol% Ni3Al, with an activation energy of <similar to>400 +/- 60 kJ/mol.