Ni_3Al-BONDED WC AND TiC HARDMETALS

摘要

Ductile nickel aluminide (Ni_3Al) alloys were used as the 'binder' phase for the fabrication of both tungsten carbide and titanium carbide (WC and TiC) hardmetal composites. Ni_3Al exhibits the unusual property that the yield strength increases with temperature (up to ～800°C), making these alloys alternatives to the Co binder in conventional cemented carbide hardmetals. Specimens with 20 and 30 vol. % binder were pressureless sintered at 1550-1600°C to densities of >95% T. D. The flexural strengths for the WC-based materials was lower than for comparable hotpressed materials due to secondary phase precipitation. The TiC-based composites had properties similar to comparable hardmetal materials made with nickel as the binder phase.