中国物理B ›› 2018, Vol. 27 ›› Issue (8): 86401-086401.doi: 10.1088/1674-1056/27/8/086401

• CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES • 上一篇    下一篇

The effect of dislocations on the thermodynamic properties of Ta single crystal under high pressure by molecular dynamics simulation

Yalin Li(李亚林), Jun Cai(蔡军), Dan Mo(莫丹), Yandong Wang(王沿东)   

  1. 1 School of Nuclear Science & Engineering, North China Electric Power University(NCEPU), Beijing 102206, China;
    2 State Key Laboratory for Advanced Metal Materials, University of Science & Technology Beijing, Beijing 100083, China
  • 收稿日期:2018-04-19 修回日期:2018-05-31 出版日期:2018-08-05 发布日期:2018-08-05
  • 通讯作者: Jun Cai E-mail:caijun@ncepu.edu.cn
  • 基金资助:

    Project supported by the National Natural Science Foundation of China (Grant No. 51231002) and the Basic Scientific Research Projects in Central Colleges and Universities (Grant No. 2018ZD10).

The effect of dislocations on the thermodynamic properties of Ta single crystal under high pressure by molecular dynamics simulation

Yalin Li(李亚林)1, Jun Cai(蔡军)1, Dan Mo(莫丹)1, Yandong Wang(王沿东)2   

  1. 1 School of Nuclear Science & Engineering, North China Electric Power University(NCEPU), Beijing 102206, China;
    2 State Key Laboratory for Advanced Metal Materials, University of Science & Technology Beijing, Beijing 100083, China
  • Received:2018-04-19 Revised:2018-05-31 Online:2018-08-05 Published:2018-08-05
  • Contact: Jun Cai E-mail:caijun@ncepu.edu.cn
  • Supported by:

    Project supported by the National Natural Science Foundation of China (Grant No. 51231002) and the Basic Scientific Research Projects in Central Colleges and Universities (Grant No. 2018ZD10).

摘要:

The thermodynamic properties of Ta metal under high pressure are studied by molecular dynamics simulation. For dislocation-free Ta crystal, all the thermodynamic properties considered are in good agreement with the results from experiments or higher level calculations. If dislocations are included in the Ta crystal, it is found that as the dislocation density increases, the hydrostatic pressure at the phase transition point of bcc→hcp and hcp→fcc decreases, while the Hugoniot temperature increases. Meanwhile, the impact pressure at the elastic-plastic transition point is found to depend on the crystallographic orientation of the pressure. As the dislocation density increases, the pressure of the elastic-plastic transition point decreases rapidly at the initial stage, then gradually decreases with the increase of the dislocation density.

关键词: Ta, high pressure, phase transition, dislocation density, molecular dynamics (MD)

Abstract:

The thermodynamic properties of Ta metal under high pressure are studied by molecular dynamics simulation. For dislocation-free Ta crystal, all the thermodynamic properties considered are in good agreement with the results from experiments or higher level calculations. If dislocations are included in the Ta crystal, it is found that as the dislocation density increases, the hydrostatic pressure at the phase transition point of bcc→hcp and hcp→fcc decreases, while the Hugoniot temperature increases. Meanwhile, the impact pressure at the elastic-plastic transition point is found to depend on the crystallographic orientation of the pressure. As the dislocation density increases, the pressure of the elastic-plastic transition point decreases rapidly at the initial stage, then gradually decreases with the increase of the dislocation density.

Key words: Ta, high pressure, phase transition, dislocation density, molecular dynamics (MD)

中图分类号:  (Equations of state of pure metals and alloys)

  • 64.30.Ef
61.50.Ks (Crystallographic aspects of phase transformations; pressure effects) 64.70.K (Solid-solid transitions) 64.70.kd (Metals and alloys)