Properties of nanostructured TiC and TiC-TiAl₃ hard materials rapidly sintered by the pulsed current activated heating

In the case of cemented TiC, Ni or Co is added as a binder for the formation of composite structures. However, the high cost of Ni or Co and the low corrosion resistance of the TiC-Ni and TiC-Co cermets have generated interest in recent years for alternative binder phases. In this study, TiAl₃ was used as a novel binder and consolidated by the pulsed current activated sintering (PCAS) method. Highly dense TiC-TiAl₃ with a relative density of up to 100% was obtained within 2 min by PCAS under a pressure of 80 MPa. The method was found to enable not only the rapid densification but also the inhibition of grain growth preserving the nano-scale microstructure. The average grain sizes of the sintered TiC and TiC-TiAl₃ were lower than 100 nm. The addition of TiAl₃ to TiC enhanced the toughness without great decrease of hardness due to crack deflection and increase of relative density.