Hydrogen behaviors in molybdenum and tungsten and a generic vacancy trapping mechanism for H bubble formation

Sun, Lu; Jin, Shuo; Li, Xiao-Chun; Zhang, Ying; Lü, Guang-Hong

doi:10.1016/j.jnucmat.2012.12.008

Cited by 80 publications

(68 citation statements)

References 47 publications

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“…20 The effect of temperature on the hydrogen accommodation has been studied by the molecular dynamics (MD) simulations which give the decrease of trapped hydrogen number in vacancy as temperature increases. 18 At 300 K, about 6.5 hydrogen atoms are trapped by a monovacancy, while the number decreases to 5 at 900 K. This is basically coincident with the thermodynamic estimation which concludes that the monovacancy can hold up to 5 hydrogen atoms at room temperature. 21 On the other hand, the anisotropic strain is shown to enhance hydrogen solubility which helps the hydrogen bubble growth.…”

Section: Introductionsupporting

confidence: 77%

“…First-principles calculations suggest that the vacancy in tungsten provides trap sites for hydrogen atoms and one vacancy could at 0 K hold at most 10 hydrogen atoms with one H 2 in the center, driven by optimal charge density. 17 This is known as the vacancy trapping mechanism 17,18 which elucidates the bubble formation at the vacancy-type defects such as vacancy and grain boundary 19 where the hydrogen bubbles are observed experimentally. 20 The effect of temperature on the hydrogen accommodation has been studied by the molecular dynamics (MD) simulations which give the decrease of trapped hydrogen number in vacancy as temperature increases.…”

Section: Introductionmentioning

confidence: 99%

“…[11][12][13] Such an energy is certainly insufficient to create new vacancies in tungsten. Since the influence of other defects like grain boundaries is excluded, it still remains an open question how the abundant vacancies essentially required by the vacancy trapping mechanism [16][17][18][19] for the hydrogen bubble formation are generated under such a condition and then how hydrogen bubbles are formed.…”

Section: Introductionmentioning

confidence: 99%

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Mechanism of vacancy formation induced by hydrogen in tungsten

et al. 2013

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We report a hydrogen induced vacancy formation mechanism in tungsten based on classical molecular dynamics simulations. We demonstrate the vacancy formation in tungsten due to the presence of hydrogen associated directly with a stable hexagonal self-interstitial cluster as well as a linear crowdion. The stability of different self-interstitial structures has been further studied and it is particularly shown that hydrogen plays a crucial role in determining the configuration of SIAs, in which the hexagonal cluster structure is preferred. Energetic analysis has been carried out to prove that the formation of SIA clusters facilitates the formation of vacancies. Such a mechanism contributes to the understanding of the early stage of the hydrogen blistering in tungsten under a fusion reactor environment.

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Section: Introductionsupporting

confidence: 77%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Mechanism of vacancy formation induced by hydrogen in tungsten

et al. 2013

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“…Ab initio and Molecular Dynamics simulations showed that H tends to occupy off-centred position in a vacancy, experiencing weak attraction to W atoms [18,19]. This implies that H atoms, when filling a void, first should occupy the inner surface positions and then fill the centre.…”

Section: Model Descriptionmentioning

confidence: 99%

Numerical analysis of TDS spectra under high and low flux plasma exposure conditions

et al. 2016

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Recently developed numerical model, based on the dislocation-driven nucleation of gas bubbles, is used to analyse experimental results on deuterium retention in tungsten under ITER relevant plasma exposure conditions. Focus is put on understanding the relation between exposure temperature and flux on primary features of thermal desorption spectra: peak positions and intensities of the desorption flux. The model allows one to relate the peak positions with the size of plasma induced deuterium bubbles and envisage exposure conditions (temperature and flux) for their formation. Based on the performed analysis, dedicated experimental conditions to validate the model are proposed.

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“…The solution energy of H in the GB is calculated to be 2.5 eV, much lower than that from the DFT calculation (1.2 eV) [42,48]. The overestimated H-GB interaction leads to the overestimated potential energy with H at the GB (more negative), but the potential energy with H far from GB remains unchanged.…”

Section: Discussionmentioning

confidence: 67%

Effect of hydrogen on grain boundary migration in tungsten

Shu

Liu

et al. 2015

Sci. China Phys. Mech. Astron.

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Motivated by a grain boundary (GB) healing mechanism that GB turns into a mobile sink through migration to eliminate the vacancies in a bulk, we have further investigated the influence of the retained hydrogen (H) on the GB migration in tungsten using a molecular dynamics simulation. We show that H hinders the GB migration at different H concentrations and temperatures, and such friction of GB migration due to the presence of H increases with the H concentration and decreases with temperature. We demonstrate that H follows the GB-migration as the temperature is higher than 300 K. Most importantly, the presence of H induces a disordering of GB, which affects the GB migration significantly. tungsten grain boundary, hydrogen, migration, molecular dynamics, disordering PACS number(s): 28.52.Fa, 61.72.Mm, 61.82.Bg, 31.15.Qg Citation: Yu Y, Shu X L, Liu Y N, et al. Effect of hydrogen on grain boundary migration in tungsten.

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Hydrogen behaviors in molybdenum and tungsten and a generic vacancy trapping mechanism for H bubble formation

Cited by 80 publications

References 47 publications

Mechanism of vacancy formation induced by hydrogen in tungsten

Mechanism of vacancy formation induced by hydrogen in tungsten

Numerical analysis of TDS spectra under high and low flux plasma exposure conditions

Effect of hydrogen on grain boundary migration in tungsten

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