FABRICATION OF TIB2/TIC COMPOSITES BY THE DIRECTIONAL REACTION OF TITANIUM WITH BORON-CARBIDE

Dense TiB2/TiC composites were fabricated by the directional reaction of molten titanium with boron carbide preform. The reaction between pure molten titanium and boron carbide preform could not progress due to reaction choking. However, when a few weight per cent of nickel were added in the titanium, the reaction progressed continuously and resulted in TiB2/TiC composites. A gradient of grain sizes was observed in the reaction products. The processing temperature affected the microstructure of the reaction products rather than the reaction rate. The degree of grain-size gradient in the reaction product increased with the processing temperature.