Mechanical properties of (W, Ti)C and (W, Ti)C-NiAl₃ cermet consolidated by the high-frequency induction-heating method

In the case of cemented (W, Ti)C, Co is added as a binder for the formation of composite structures. However, the high cost of Co and the low corrosion resistance of the (W, Ti)C-Co cermet have generated interest in recent years for alternative binder phases. In this study, NiAl₃ was used as a binder and consolidated by the high-frequency induction heated sintering (HFIHS) method. The densification of both monolithic (W, Ti)C and (W, Ti)C-NiAl ₃ cermet was accomplished within 3 min. Highly dense (W, Ti)C and (W, Ti)C-NiAl₃ with a relative density of upto 99% were obtained within 3 min by HFIHS under a pressure of 80 MPa. The method was found to enable not only the rapid densification but also the prohibition of grain growth preserving the nano-scale microstructure. The average grain sizes of the sintered (W, Ti)C and (W, Ti)C-NiAl₃ were lower than 100 nm. The addition of NiAl ₃ to (W, Ti)C enhanced the toughness at the expense of the slight decrease in hardness. The hardness of (W, Ti)C and (W, Ti)C-NiAl₃ was significantly higher than that of (W, Ti)C-Co or (W, Ti)C-Ni. The fracture toughness and hardness values of (W, Ti)C, (W, Ti)C-5vol.%NiAl₃, and (W, Ti)C-10vol.%NiAl₃ consolidated by HFIHS with a pressure of 80 MPa and a induced current were 7.6 ± 0.4 MPa m^1/2 and 2850 ± 35 kg/mm², 8.5 ± 0.3 MPa m^1/2 and 2610 ± 37 kg/mm², 9.7 ± 0.5 MPa m^1/2 and 2520 ± 26 kg/mm², respectively.