Processing and mechanical properties of nonstoichiometric TiC (0.3 ≤ x ≤ 0.5)

Abstract Titanium carbide (TiC) has been considered as one of the most significant metal carbides for manufacturing a new generation of cermets. However, overhigh sintering temperature results in that dense sintered-bulk of TiC without metal binders is hard to realize at relative low temperature, which limits its applications. Here, we prepared nonstoichiometric TiCx (0.3 ≤ x ≤ 0.5) powers with carbon vacancy defects by mechanical alloying (MA) and then sintered into a cylindrical compact at high temperature and high pressure (HTHP). The mechanical properties of nonstoichiometric TiCx were obtained by an indentation method. Vickers hardness of TiC0.3, TiC0.4 and TiC0.5 compacts are 15 GPa, 25 GPa and 24 GPa, fracture toughness of TiC0.3, TiC0.4 and TiC0.5 are 6 MPa m1/2, 3.8 MPa m1/2 and 3.5 MPa m1/2, respectively. Our studies indicate that introduction of carbon vacancies dramatically reduces the sintering temperature because of diffusion paths provided by carbon vacancies, without the deterioration of the mechanical properties. The successful synthesis of TiCx bulks may provide a low-temperature sintering route for refractory ceramic compounds such as VC, NbC and WC, etc.