Fabrication of TiB2-Fe-Al Cermet Alloys Synthesized by Pulsed Current Process

Mechanical alloying and pulsed-current sintering were used to synthesize TiB2-Fe-Al cermet alloys consisting of titanium boride and iron aluminide intermetallic compound. A mixture was obtained to which Fe was minutely distributed by mechanically alloying TiB2 powder and Fe powder for 180 ks. Mixture powders of TiB2-20 mass%Fe3Al and of TiB2-24 mass%FeAl were prepared by mixing an Al powder with this mechanically alloyed powder using a mortar. The added Al reacted with Fe after it had melted when these mixtures were heated. These powders were sintered for a short time and at low temperature using pulsed-current sintering process, but these sintered compacts had pores. Several iron aluminide intermetallic compounds were generated in the TiB2-20 mass%Fe3Al. Therefore, the TiB2-20 mass%Fe3Al compact was hard and brittle. However, the TiB2-24 mass%FeAl sintered body was composed only of TiB2 and FeAl, and had better ductility. A slight weight increase resulted from oxidation even though it was heated to 800 K or more in the air, but both sintered compacts retained their pores.