Preparation of dense TiN1 − X (X = 0–0.4) by pulsed electric current sintering: Densification and mechanical behavior

• Dense bulks of TiN1 − X were prepared by a new method reacting TiN with TiH2 by pulsed electric current sintering.
• The addition of TiH2 promotes densification and grain growth.
• Negligible existence of impurities and shorter times was achieved compared with previous reports.
• A maximum Vickers hardness was obtained at X = 0.3 in TiN1 − X without significant degradation in fracture toughness.
• The hardness of TiN1 − X can be controlled as function of TiH2/TiN ratio.

Bulks of TiN1 − X in the range of X = 0–0.4 with high density were prepared by a new method which comprises the reaction between TiN with TiH2 through pulsed electric current sintering. X-ray diffractograms revealed that single fcc phase with nitrogen vacancies was achieved after sintering; further observation by scanning electron microscopy showed homogeneous structure in all samples and larger grain size by increasing the amount of TiH2. The maximum Vickers hardness measured on the samples was approximately 31 GPa at X = 0.3. An increase in hardness was observed in non-stoichiometric samples even its larger grain size. The grain size-indent diagonal ratio was calculated from 1.2 at X = 0 to 5.6 at X = 0.4. The addition of TiH2 showed an improvement in both densification and hardness without significant degradation of fracture toughness. Based on these results, the mechanical properties of TiN1 − X bulks can be controlled as a function of TiH2/TiN ratios in order to be used for different applications.