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

• Nearly full-dense nanostructured TiC–TiAl3 composites could be obtained within 2 min.
• The starting temperature of rapid densification of TiC were reduced remarkably by the addition of TiAl3.
• The addition of TiAl3 to TiC improved the fracture toughness of cemented TiC.
• It would be worthwhile to consider TiAl3 as the possible replacement for Co or Ni.
• It is believed that TiC and TiAl3 in the composite may deter the propagation of cracks.

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.