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

• Using high-frequency induction heated sintering (HFIHS), the rapid consolidation of the nanostructured (W,Ti)C, (W,Ti)C-5vol.%NiAl3, and (W,Ti)C-10vol.%NiAl3 was accomplished successfully.
• The densification temperature of (W,Ti)C was reduced remarkably by the addition of NiAl3.
• The addition of NiAl3 to (W,Ti)C improved the fracture toughness of cemented (W,Ti)C without an extensive loss of its hardness.
• The hardness values of (W,Ti)C added as novel binder of NiAl3 were higher than those of WC added as conventional binder of Ni or Co.

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–NiAl3 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 NiAl3 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 m1/2 and 2850 ± 35 kg/mm2, 8.5 ± 0.3 MPa m1/2 and 2610 ± 37 kg/mm2, 9.7 ± 0.5 MPa m1/2 and 2520 ± 26 kg/mm2, respectively.