中国物理B ›› 2018, Vol. 27 ›› Issue (7): 73103-073103.doi: 10.1088/1674-1056/27/7/073103

• SPECIAL TOPIC—Recent advances in thermoelectric materials and devices • 上一篇    下一篇

Diffusion behavior of hydrogen isotopes in tungsten revisited by molecular dynamics simulations

Mingjie Qiu(丘明杰), Lei Zhai(翟磊), Jiechao Cui(崔节超), Baoqin Fu(付宝勤), Min Li(李敏), Qing Hou(侯氢)   

  1. Key Laboratory for Radiation Physics and Technology(Ministry of Education), Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610064, China
  • 收稿日期:2018-01-10 修回日期:2018-04-26 出版日期:2018-07-05 发布日期:2018-07-05
  • 通讯作者: Qing Hou E-mail:qhou@scu.edu.cn
  • 基金资助:

    Project supported by the National Magnetic Confinement Fusion Program of China (Grant No. 2013GB109002).

Diffusion behavior of hydrogen isotopes in tungsten revisited by molecular dynamics simulations

Mingjie Qiu(丘明杰), Lei Zhai(翟磊), Jiechao Cui(崔节超), Baoqin Fu(付宝勤), Min Li(李敏), Qing Hou(侯氢)   

  1. Key Laboratory for Radiation Physics and Technology(Ministry of Education), Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610064, China
  • Received:2018-01-10 Revised:2018-04-26 Online:2018-07-05 Published:2018-07-05
  • Contact: Qing Hou E-mail:qhou@scu.edu.cn
  • Supported by:

    Project supported by the National Magnetic Confinement Fusion Program of China (Grant No. 2013GB109002).

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摘要：

Molecular dynamics simulations were performed to study the diffusion behavior of hydrogen isotopes in single-crystal tungsten in the temperature range of 300-2000 K. The simulations show that the diffusion coefficient of H isotopes exhibits non-Arrhenius behavior, though this deviation from Arrhenius behavior is slight. Many-body and anharmonic effects of the potential surface may induce slight isotope-dependence by the activation energy; however, the dependence of the pre-factor of the diffusion coefficient on the isotope mass is diminished. The simulation results for H-atom migration near W surfaces suggest that no trap mutations occur for H atoms diffusing near either W{100} or W{111} surfaces, in contrast to the findings for He diffusion near W surfaces. Based on the H behavior obtained by our MD simulations, the time evolution of the concentration distribution of interstitial H atoms in a semi-infinite W single crystal irradiated by energetic H projectiles was calculated. The effect of H concentration on H diffusion is discussed, and the applicability of the diffusion coefficients obtained for dilute H in W is assessed.

关键词: hydrogen isotopes, tungsten, diffusion, molecular dynamics

Abstract:

Molecular dynamics simulations were performed to study the diffusion behavior of hydrogen isotopes in single-crystal tungsten in the temperature range of 300-2000 K. The simulations show that the diffusion coefficient of H isotopes exhibits non-Arrhenius behavior, though this deviation from Arrhenius behavior is slight. Many-body and anharmonic effects of the potential surface may induce slight isotope-dependence by the activation energy; however, the dependence of the pre-factor of the diffusion coefficient on the isotope mass is diminished. The simulation results for H-atom migration near W surfaces suggest that no trap mutations occur for H atoms diffusing near either W{100} or W{111} surfaces, in contrast to the findings for He diffusion near W surfaces. Based on the H behavior obtained by our MD simulations, the time evolution of the concentration distribution of interstitial H atoms in a semi-infinite W single crystal irradiated by energetic H projectiles was calculated. The effect of H concentration on H diffusion is discussed, and the applicability of the diffusion coefficients obtained for dilute H in W is assessed.

Key words: hydrogen isotopes, tungsten, diffusion, molecular dynamics

中图分类号:  (Molecular dynamics and other numerical methods)

  • 31.15.xv
52.40.Hf (Plasma-material interactions; boundary layer effects) 52.65.Yy (Molecular dynamics methods) 66.30.J- (Diffusion of impurities ?)