A new loop-punching mechanism for helium bubble growth in tungsten

Xie, Hongxian; Gao, Ning; Xu, Ke; Lü, Guang-Hong; Yu, Tao; Yin, Fuxing

doi:10.1016/j.actamat.2017.09.005

Cited by 77 publications

(34 citation statements)

References 33 publications

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“…Gao et al [31] proposed that, before forming crowdion along <111> direction, interstitials may create stable configurations with the formation of a <110> dumbbell in Fe, which is consistent with Xiao’s work [37]. In addition, a transition from <100> interstitial cluster to <111> interstitial cluster is identified in tungsten [29,49]. This process is energetically favorable with an energy release of 1.12 eV, indicating that the <111> SIAs cluster is more stable.…”

Section: Helium Bubble Nucleation Growth and Coarseningsupporting

confidence: 63%

“…The crowdion structure is observed to be temporarily trapped by He bubbles once formed [31,32,33,34,37,48,49]. Notably, the crowdion structure usually exhibits an energetically favorable orientation along <111> direction in BCC metals [27,29,31,37,49]. With further increasing He concentration, SIAs accumulate continuously around He bubbles, giving rise to the formation and emission of dislocation loops.…”

Section: Helium Bubble Nucleation Growth and Coarseningmentioning

confidence: 99%

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Radiation-Induced Helium Bubbles in Metals

Han

2019

Materials

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Helium (He) bubbles are typical radiation defects in structural materials in nuclear reactors after high dose energetic particle irradiation. In the past decades, extensive studies have been conducted to explore the dynamic evolution of He bubbles under various conditions and to investigate He-induced hardening and embrittlement. In this review, we summarize the current understanding of the behavior of He bubbles in metals; overview the mechanisms of He bubble nucleation, growth, and coarsening; introduce the latest methods of He control by using interfaces in nanocrystalline metals and metallic multilayers; analyze the effects of He bubbles on strength and ductility of metals; and point out some remaining questions related to He bubbles that are crucial for design of advanced radiation-tolerant materials.

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Section: Helium Bubble Nucleation Growth and Coarseningsupporting

confidence: 63%

Section: Helium Bubble Nucleation Growth and Coarseningmentioning

confidence: 99%

Radiation-Induced Helium Bubbles in Metals

Han

2019

Materials

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“…The pressure in a helium bubble that is far from a surface or grain boundary and which has not yet burst should be greater than or equal to the equilibrium pressure, P eq . As established in prior work [38][39][40][41][42][43][44] , pressure in growing bubbles is relieved by "punching out" dislocation loops, called "loop-punching". The pressure should therefore be less than or approximately equal to the loop-punching stress; as helium is arriving at the bubbles much faster than vacancies are, we expect the pressure inside most bubbles to be closer to the critical value corresponding to loop-punching than to the equilibrium pressure.…”

mentioning

confidence: 97%

Theoretical Model of Helium Bubble Growth and Density in Plasma-Facing Metals

Hammond

Maroudas

Wirth

2020

Sci Rep

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We present a theoretically-motivated model of helium bubble density as a function of volume for high-pressure helium bubbles in plasma-facing tungsten. the model is a good match to the empirical correlation we published previously [Hammond et al., Acta Mater. 144, 561-578 (2018)] for small bubbles, but the current model uses no adjustable parameters. The model is likely applicable to significantly larger bubbles than the ones examined here, and its assumptions can be extended trivially to other metals and gases. We expect the model to be broadly applicable and useful in coarse-grained models of gas transport in metals.

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“…Based on the calculation of SRIM-2013, the ratio of concentrations of helium atoms to vacancies introduced by irradiation in S7 was higher than that in S2. It has been recognized that loop punching may occur for helium [ 34 , 35 ]. When n/m is larger than a criterion (n/m > 3, according to the literature [ 30 ]), the binding energy of a SIA with He n V m clusters is smaller than that of a helium atom with He n V m clusters.…”

Section: Resultsmentioning

confidence: 99%

Investigation of Helium Behavior in RAFM Steel by Positron Annihilation Doppler Broadening and Thermal Desorption Spectroscopy

et al. 2018

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The behavior of helium in reduced-activation ferritic/martensitic steels was investigated systematically with positron annihilation Doppler broadening measurement and thermal desorption spectroscopy. Specimens were irradiated with helium ions with different energies to various fluences at different temperatures. A threshold fluence was observed above which the rate of formation and growth of helium bubbles dramatically increased. Irradiation at higher temperature could suppress the formation and growth of HenVm clusters with low binding energies and enhance that of helium bubbles and HenVm clusters with high binding energies. Different changes of S parameters were observed in various depth after the irradiation temperature was increased from 523 K to 723 K. Irradiation of 18 keV-He+ enhanced the growth of HenVm clusters and helium bubbles compared with 100 keV-He+ irradiation. A possible mechanism is discussed.

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A new loop-punching mechanism for helium bubble growth in tungsten

Cited by 77 publications

References 33 publications

Radiation-Induced Helium Bubbles in Metals

Radiation-Induced Helium Bubbles in Metals

Theoretical Model of Helium Bubble Growth and Density in Plasma-Facing Metals

Investigation of Helium Behavior in RAFM Steel by Positron Annihilation Doppler Broadening and Thermal Desorption Spectroscopy

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