J. Mater. Sci. Technol. ›› 2018, Vol. 34 ›› Issue (10): 1953-1958.DOI: 10.1016/j.jmst.2018.02.012

Special Issue: 材料计算 2018

• Orginal Article • Previous Articles     Next Articles

A first-principles investigation on mechanical and metallic properties of titanium carbides under pressure

Xiaojing Sha, Namin Xiao, Yongjun Guan, Xiaosu Yi()   

  1. Materials Genome Center, Beijing Institute of Aeronautical Materials, Beijing 100095, China
  • Received:2017-06-01 Revised:2017-07-17 Accepted:2017-07-21 Online:2018-10-05 Published:2018-11-01

Abstract:

The titanium carbides are potential candidates to achieve both high hardness and refractory property. We carried out a structural search for titanium carbides at three pressures of 0 GPa, 30 GPa and 50 GPa. A phase diagram of the Ti-C system at 0 K was obtained by elucidating formation enthalpies as a function of compositions, and their mechanical and metallic properties of titanium carbides were investigated systematically. We also discussed the relation of titanium concentration to the both mechanical and metallic properties of titanium carbides. It has been found that the average valence electron density and tractility improved at higher concentrations of titanium, while the degree of covalent bonding directionality decreased. To this effect, the hardness of titanium carbide decreases as the content of titanium increases. Our results indicated that the titanium content significantly affected the metallic properties of the Ti-C system.

Key words: First-principles calculation, Transition metal carbides, Mechanical property and hardness, High pressure phase stability