中国物理B ›› 2016, Vol. 25 ›› Issue (7): 76602-076602.doi: 10.1088/1674-1056/25/7/076602

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

Diffusion behavior of helium in titanium and the effect of grain boundaries revealed by molecular dynamics simulation

Gui-Jun Cheng(程贵钧), Bao-Qin Fu(付宝勤), Qing Hou(侯氢), Xiao-Song Zhou(周晓松), Jun Wang(汪俊)   

  1. 1 Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900, China;
    2 Key Laboratory for Radiation Physics and Technology, Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610065, China
  • 收稿日期:2016-01-29 修回日期:2016-03-15 出版日期:2016-07-05 发布日期:2016-07-05
  • 通讯作者: Bao-Qin Fu E-mail:bqfu@scu.edu.cn
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No. 51501119), the Scientific Research Starting Foundation for Younger Teachers of Sichuan University, China (Grant No. 2015SCU11058), the National Magnetic Confinement Fusion Science Program of China (Grant No. 2013GB109002), and the Cooperative Research Project “Research of Diffusion Behaviour of He in Grain Boundary of HCP-Titanium”, China.

Diffusion behavior of helium in titanium and the effect of grain boundaries revealed by molecular dynamics simulation

Gui-Jun Cheng(程贵钧)1, Bao-Qin Fu(付宝勤)2, Qing Hou(侯氢)2, Xiao-Song Zhou(周晓松)1, Jun Wang(汪俊)2   

  1. 1 Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900, China;
    2 Key Laboratory for Radiation Physics and Technology, Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610065, China
  • Received:2016-01-29 Revised:2016-03-15 Online:2016-07-05 Published:2016-07-05
  • Contact: Bao-Qin Fu E-mail:bqfu@scu.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No. 51501119), the Scientific Research Starting Foundation for Younger Teachers of Sichuan University, China (Grant No. 2015SCU11058), the National Magnetic Confinement Fusion Science Program of China (Grant No. 2013GB109002), and the Cooperative Research Project “Research of Diffusion Behaviour of He in Grain Boundary of HCP-Titanium”, China.

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摘要： The microstructures of titanium (Ti), an attractive tritium (T) storage material, will affect the evolution process of the retained helium (He). Understanding the diffusion behavior of He at the atomic scale is crucial for the mechanism of material degradation. The novel diffusion behavior of He has been reported by molecular dynamics (MD) simulation for the bulk hcp-Ti system and the system with grain boundary (GB). It is observed that the diffusion of He in the bulk hcp-Ti is significantly anisotropic (the diffusion coefficient of the [0001] direction is higher than that of the basal plane), as represented by the different migration energies. Different from convention, the GB accelerates the diffusion of He in one direction but not in the other. It is observed that a twin boundary (TB) can serve as an effective trapped region for He. The TB accelerates diffusion of He in the direction perpendicular to the twinning direction (TD), while it decelerates the diffusion in the TD. This finding is attributable to the change of diffusion path caused by the distortion of the local favorable site for He and the change of its number in the TB region.

关键词: diffusion, grain boundary, helium and titanium, molecular dynamics

Abstract: The microstructures of titanium (Ti), an attractive tritium (T) storage material, will affect the evolution process of the retained helium (He). Understanding the diffusion behavior of He at the atomic scale is crucial for the mechanism of material degradation. The novel diffusion behavior of He has been reported by molecular dynamics (MD) simulation for the bulk hcp-Ti system and the system with grain boundary (GB). It is observed that the diffusion of He in the bulk hcp-Ti is significantly anisotropic (the diffusion coefficient of the [0001] direction is higher than that of the basal plane), as represented by the different migration energies. Different from convention, the GB accelerates the diffusion of He in one direction but not in the other. It is observed that a twin boundary (TB) can serve as an effective trapped region for He. The TB accelerates diffusion of He in the direction perpendicular to the twinning direction (TD), while it decelerates the diffusion in the TD. This finding is attributable to the change of diffusion path caused by the distortion of the local favorable site for He and the change of its number in the TB region.

Key words: diffusion, grain boundary, helium and titanium, molecular dynamics

中图分类号:  (Diffusion of impurities ?)

  • 66.30.J-
61.72.Mm (Grain and twin boundaries) 66.30.-h (Diffusion in solids) 61.72.-y (Defects and impurities in crystals; microstructure)