Chinese Journal of Computational Physics ›› 2023, Vol. 40 ›› Issue (1): 40-46.DOI: 10.19596/j.cnki.1001-246x.8543

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First-principles Study of Structures, Mechanical Properties and Electronic Properties of Quaternary Hf-Ta-C-N System

Xiang CHENG1(), Junwei FENG2, Tikhonov EVGENII3   

  1. 1. Science and Technology College of NCHU, Gongqingcheng, Jiangxi 332020, China
    2. Computer-automated Materials Design Laboratory, Xi'an, Shaanxi 710068, China
    3. School of Materials Science and Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, China
  • Received:2022-04-12 Online:2023-01-25 Published:2023-07-04

Abstract:

Based on evolutionary algorithm and first-principles calculation, crystal structures of quaternary compound HfxTa8-xC7N (x=1-7) were predicted. Similar to binary HfC and TaC, these compounds have a rock-salt structure. The calculation of mechanical properties shows that: With the increase of valence electron concentration (VEC), the bulk modulus of HfxTa8-xC7N increased gradually; At VEC=8.875, the shear modulus and elastic modulus are the largest; The Vickers hardness reaches the maximum at VEC=8.25. Therefore, the quaternary HfxTa8-xC7N compounds with excellent comprehensive mechanical properties can be obtained with the design of VEC. Finally, electronic properties of HfxTa8-xC7N compounds were calculated. Relations between mechanical properties and electronic properties were analyzed.

Key words: HfxTa8-xC7N, crystal structure prediction, effective valence electron concentration, first-principles calculation