Effect of WC content on microstructure and mechanical properties of Ni3Al-bonded cermets

The effect of WC content on microstructure and mechanical properties of the TiC-Ni3Al system cermets was investigated. Ni3Al-bonded cermets showed a core-rim structure with carbide particle coupled with rim embedded in Ni3Al binder. With WC content increasing, TiC grains were refined and the white rim became complete and got thicker gradually. Interface between core and rim showed a completely coherent relationship. The rim enriched in W constituted an ideal coherence between hard phase and Ni3Al binder phase. With WC content increasing, the densification of cermets was enhanced, and hardness and TRS were increased firstly and then reduced, reaching peak values 90.9 HRA (HV30 15 GPa) and 1629 MPa, respectively in cermet N5 (25 wt% WC). Similarly, fracture toughness got a peak value (11.6 MPa m1/2), at the composition with 20 wt% WC.