Ab initio static and molecular dynamics studies of helium behavior in beryllium

Vladimirov, P.; Moeslang, A.

doi:10.1016/j.jnucmat.2013.04.041

Cited by 16 publications

(12 citation statements)

References 14 publications

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“…4(a), which is comparable to previous theoretical values of 0.36 eV 27 and 0.37 eV. 18 As to the path of two nearest-neighbor BT sites, the CI-NEB calculations directly show that the migration energy barrier is 0.331 eV as demonstrated in Fig. 4(b).…”

Section: B Migration Energy Barriers Of Helium In α-Be Crystalsupporting

confidence: 87%

“…Furthermore, we have calculated the binding energy of helium atom with a Be vacancy of 2.402 eV, which suggests that the substitutional helium atom is almost irreversibly trapped by vacancy and requires another vacancy for diffusion. This prediction is confirmed by Vladimirov et al, 18,36 who found that the substitutional helium only diffuses as a vacancy cluster and the diffusion barrier is in the range of 0.7 eV ∼ 1.6 eV in the basal plane. This results in the quick and efficient capture of interstitial helium atoms by vacancies, and diffusion coefficient is thus reduced greatly.…”

Section: Diffusion Coefficientssupporting

confidence: 63%

“…Cell size 96-atom cell 96-atom cell 27 96-atom cell 18 128-atom cell 18 E cut (eV) 600 300 450 450 k points 9 × 9 × 9 9 × 9 × 9 13 × 13 × 13 13 ), which makes interstitial helium energetically unfavorable.…”

Section: Current Results Previous Resultsmentioning

confidence: 99%

“…17 Besides, molecular dynamics methods are used to study the behaviors of helium in neutron irradiated beryllium as well. 18 Furthermore, the vacancy trapping mechanism for helium in beryllium is investigated with a first-principles method. 19 Nevertheless, the theoretical papers devoted to the atomic-scale mechanisms for helium diffusion and interaction with the surroundings in beryllium are still scarce.…”

Section: Introductionmentioning

confidence: 99%

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

Yang

et al. 2016

AIP Advances

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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.

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Section: B Migration Energy Barriers Of Helium In α-Be Crystalsupporting

confidence: 87%

Section: Diffusion Coefficientssupporting

confidence: 63%

Section: Current Results Previous Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

Yang

et al. 2016

AIP Advances

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“…Being lightweight metal, beryllium finds numerous technological applications ranging from aerospace and nuclear industry to mobile phones due to its exceptional physical properties such as high strength, electrical conductivity and high melting point. It has an anisotropic hexagonal close packed crystal lattice structure, which controls the complex properties of irradiation-induced self-point defects and dissolved foreign atoms 1,2 . Their dynamic interplay with dislocations and grain boundaries (GBs) determines the microstructure evolution under irradiation.…”

mentioning

confidence: 99%

New insights into microstructure of irradiated beryllium based on experiments and computer simulations

Klimenkov

Vladimirov

Jäntsch

et al. 2020

Sci Rep

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The microstructural response of beryllium after neutron irradiation at various temperatures (643-923 K) was systematically studied using analytical transmission electron microscope that together with outcomes from advanced atomistic modelling provides new insights in the mechanisms of microstructural changes in this material. The most prominent feature of microstructural modification is the formation of gas bubbles, which is revealed at all studied irradiation temperatures. except for the lowest irradiation temperature, gas bubbles have the shape of thin hexagonal prisms with average height and diameter increasing with temperature. A high number density of small bubbles is observed within grains, while significantly larger bubbles are formed along high-angle grain boundaries (GB). Denuded zones (DZ) nearly free from bubbles are found along both high-and low-angle grain boundaries. Precipitations of secondary phases (mainly intermetallic Al-Fe-Be) were observed inside grains, along dislocation lines and at GBs. EDX analysis has revealed homogeneous segregation of chromium and iron along GBs. the observed features are discussed with respect to the available atomistic modelling results. in particular, we present a plausible reasoning for the abundant formation of gas bubbles on intermetallic precipitates, observation of various thickness of zones denuded in gas bubbles and precipitates, and their relation to the atomic scale diffusion mechanisms of solute-vacancy clusters.

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