Properties and Rapid Consolidation of Nanostructured TiC and TiC–TiAl Hard Materials by High-Frequency Induction Heating

Abstract

For the formation of composite structures, Co or Ni is added as a binder, in the case of cemented TiC. However, the high cost of Co or Ni, and the low corrosion resistance of TiC–Co or TiC–Ni cermet have generated interest in recent years to find alternative binder phases. It has been reported that aluminides show higher oxidation resistance and hardness, and cheaper materials, compared to Co or Ni. Using a high-frequency induction heated sintering (HFIHS) method, the densification of TiC and TiC–TiAl hard materials was accomplished within 3 min. The advantages of this process are the prohibition of grain growth in nano-structured materials, and the rapid densification to near theoretical density. Highly dense TiC–TiAl hard materials with a relative packing density of up to 100% were obtained by HFIHS, under a pressure of 80 MPa. The average grain size of the TiC was lower than 100 nm. The addition of TiAl to TiC significantly improves the fracture toughness of cemented TiC, without greatly decreasing the hardness.