First-principles study of migration and diffusion mechanisms of helium in α-Be

Yang, Xiao-Yong; Lu, Yong; Li, Meng-Lei; Zhang, Ping

doi:10.1063/1.4944950

Title: First-principles study of migration and diffusion mechanisms of helium in α-Be

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Abstract

The behavior of interstitial helium in α-Be has been studied with first-principles method. It is found that the most favored position for helium is the basal octahedral (BO) site, closely followed by the basal tetrahedral (BT) site, in agreement with previous predictions. The interaction energy between the helium and the neighborhood Be atoms and the deformation energy of α-Be matrix are calculated. The feasible minimum-energy pathways (MEP) of interstitial helium atoms in α-Be matrix and the corresponding atomic structures of the saddle points associated with the each MEP are investigated. The temperature-dependent diffusion coefficients have also been predicted. It is confirmed that the interstitial helium diffuses two-dimensionally at low temperatures; however, it can diffuse three-dimensionally at higher temperatures. Besides, the microscopic parameters in the pre-factor and activation energy of the diffusion coefficients are obtained. Both diffusion coefficients are higher than the available experiment data, which may attribute to the fact that under real condition the diffusion is not free, i.e. the actual α-Be matric has various defects and impurities which heavily affect the diffusion of helium. Therefore, our theoretical prediction is the upper bound for helium diffusion in α-Be matrix.

Authors:

Yang, Xiao-Yong; Lu, Yong ^[1]; Li, Meng-Lei; Zhang, Ping ^[1]

Institute of Applied Physics and Computational Mathematics, P.O. Box 8009, Beijing 100088 (China)

Publication Date:: Tue Mar 15 00:00:00 EDT 2016

OSTI Identifier:: 22611584

Resource Type:: Journal Article

Journal Name:: AIP Advances

Additional Journal Information:: Journal Volume: 6; Journal Issue: 3; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 2158-3226

Country of Publication:: United States

Language:: English

Subject:: 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ACTIVATION ENERGY; ATOMS; BERYLLIUM; COMPUTERIZED SIMULATION; DEFECTS; DEFORMATION; DIFFUSION; FORECASTING; HELIUM; IMPURITIES; INTERACTIONS; MIGRATION; TEMPERATURE DEPENDENCE; THREE-DIMENSIONAL CALCULATIONS; THREE-DIMENSIONAL LATTICES; TWO-DIMENSIONAL CALCULATIONS; TWO-DIMENSIONAL SYSTEMS

Citation Formats


                    Yang, Xiao-Yong, Lu, Yong, Li, Meng-Lei, Zhang, Ping, and Center for Fusion Energy Science and Technology, China Academy of Engineering Physics, Beijing 100088. First-principles study of migration and diffusion mechanisms of helium in α-Be.  United States: N. p., 2016. 
        Web.  doi:10.1063/1.4944950.

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                    Yang, Xiao-Yong, Lu, Yong, Li, Meng-Lei, Zhang, Ping, & Center for Fusion Energy Science and Technology, China Academy of Engineering Physics, Beijing 100088. First-principles study of migration and diffusion mechanisms of helium in α-Be.  United States.  https://doi.org/10.1063/1.4944950

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                    Yang, Xiao-Yong, Lu, Yong, Li, Meng-Lei, Zhang, Ping, and Center for Fusion Energy Science and Technology, China Academy of Engineering Physics, Beijing 100088. 2016.  
        "First-principles study of migration and diffusion mechanisms of helium in α-Be".  United States.  https://doi.org/10.1063/1.4944950.

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@article{osti_22611584,

  title        = {First-principles study of migration and diffusion mechanisms of helium in α-Be},

  author       = {Yang, Xiao-Yong and Lu, Yong and Li, Meng-Lei and Zhang, Ping and Center for Fusion Energy Science and Technology, China Academy of Engineering Physics, Beijing 100088},

  abstractNote = {The behavior of interstitial helium in α-Be has been studied with first-principles method. It is found that the most favored position for helium is the basal octahedral (BO) site, closely followed by the basal tetrahedral (BT) site, in agreement with previous predictions. The interaction energy between the helium and the neighborhood Be atoms and the deformation energy of α-Be matrix are calculated. The feasible minimum-energy pathways (MEP) of interstitial helium atoms in α-Be matrix and the corresponding atomic structures of the saddle points associated with the each MEP are investigated. The temperature-dependent diffusion coefficients have also been predicted. It is confirmed that the interstitial helium diffuses two-dimensionally at low temperatures; however, it can diffuse three-dimensionally at higher temperatures. Besides, the microscopic parameters in the pre-factor and activation energy of the diffusion coefficients are obtained. Both diffusion coefficients are higher than the available experiment data, which may attribute to the fact that under real condition the diffusion is not free, i.e. the actual α-Be matric has various defects and impurities which heavily affect the diffusion of helium. Therefore, our theoretical prediction is the upper bound for helium diffusion in α-Be matrix.},

  doi          = {10.1063/1.4944950},

  url          = {https://www.osti.gov/biblio/22611584},
  journal      = {AIP Advances},

  issn         = {2158-3226},

  number       = 3,

  volume       = 6,

  place        = {United States},

  year         = {Tue Mar 15 00:00:00 EDT 2016},

  month        = {Tue Mar 15 00:00:00 EDT 2016}

}

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