A molecular dynamics simulation study of temperature and depth effect on helium bubble releasing from Ti surface

Liang, Li; Ma, Ming; Wang, Xiang; Wang, Yuan; Cheng, Yanlin; Tan, Xiaohua

doi:10.1016/j.jallcom.2015.01.084

Cited by 10 publications

(3 citation statements)

References 18 publications

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“…The mechanisms of fuzz formation are complicated and difficult to probe, experimentally or computationally, but considerable effort has been undertaken to understand them [11], and there have been efforts undertaken to mitigate the formation of fuzz [12]. Computational studies of plasma-facing materials are an important part of this effort [11,13,14], and to date such studies have contributed significantly to our understanding of helium bubble formation and growth [15][16][17][18][19][20][21][22][23], helium cluster mobility and dynamics near sinks such as surfaces and grain boundaries [23][24][25][26][27][28][29][30][31], and bubble rupture [19,[32][33][34][35][36][37][38][39]. Molecular dynamics simulations, in particular, have helped to elucidate the mechanisms of helium-induced effects in metals, as well as serving as important benchmarks for more coarsegrained simulation methods such as kinetic Monte Carlo [40,41] and cluster dynamics [42][43][44][45][46][47][48][49].…”

Section: Discussionmentioning

confidence: 99%

Helium flux effects on bubble growth and surface morphology in plasma-facing tungsten from large-scale molecular dynamics simulations

et al. 2019

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We investigate helium flux effects on helium transport and surface evolution in plasma-facing tungsten using molecular dynamics. The simulations span two orders of magnitude, from ITER-relevant levels to those more typical of simulations published to date. Simulation times of up to 2.5 µs (corresponding to actual fluences of m−2) are achieved, revealing concerted bubble-bursting events that are responsible for significant and very sudden changes in surface morphology. The depth distribution of helium depends very strongly on helium flux: helium self-trapping becomes more probable near the surface at high flux, and a layer of near-surface bubbles forms. Helium retention prior to the onset of bubble bursting is also substantially lower at low flux than it is at high flux. Surface features at low fluence are correlated with the positions of bubbles, but at high fluence, bubbles tend to coalesce, venting to the surface at one or more locations and leaving large interconnected cavities below the surface. Ruptured bubbles may serve as pathways deeper into the material, allowing helium to bypass the layer of near-surface bubbles and fill deeper, potentially much larger, bubbles that can produce more substantial surface features. Deeper bubbles also emit prismatic dislocation loops that can fill in cavities closer to the surface. Our results suggest that nearly all molecular dynamics simulations published to date are hampered by finite-size effects, and that helium flux is a very important parameter in determining the behavior of helium in plasma-facing components.

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Section: Discussionmentioning

confidence: 99%

Helium flux effects on bubble growth and surface morphology in plasma-facing tungsten from large-scale molecular dynamics simulations

et al. 2019

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“…Nuclear fusion reactor structural materials are not only influenced by the high temperature and high dose of neutron irradiation, and gas (such as He) may also be generated by nuclear transmutation into the material [12,13]. As helium has an extremely low solubility in the metals (about 10e5 at.%), blisters (hollow dome-shape protrusions) and bubble formed by the accumulation of gas particles near the surface regions and the internal matrix of materials to cause microstructure damage and performance degradation.…”

Section: Introductionmentioning

confidence: 99%

Surface and internal microstructure damage of He-ion-irradiated CLAM steel studied by cross-sectional transmission electron microscopy

Liu

et al. 2015

Journal of Alloys and Compounds

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“…The He atoms gradually form He clusters or bubbles by self-trapping and trapping other defects such as vacancies. When the pressure of He clusters or bubbles exceeds the critical value, they burst and release He atoms at the nanochannel surface [51,52]. However, due to the lack of free surface in the bulk W, He atoms can not be released in time to form large He clusters or bubbles.…”

Section: Simulationmentioning

confidence: 99%

Review on helium behaviors in nanochannel tungsten film

et al. 2021

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Tungsten (W) as plasma facing material (PFM) needs to face an unprecedented harsh environment in the fusion reactor, which puts forward high requirements for its radiation tolerance. Among the many challenges, the rapid accumulation of helium (He) atoms to form numerous bubbles or even "fuzzy" nanostructure leads to swelling and embrittlement of W matrix and seriously shorten its service life, which is one of the most serious problems faced by PFM-W at present. In this review, we summarize the recent works on the nanochannel W films with high surface-to-volume ratio deposited by magnetron sputtering, and the behaviors of He in the nanochannel W films at different fusion-related irradiation environment. Experimental and simulation results showed that the nanochannel W films have better radiation tolerance performance in managing He behaviors than that of commercial bulk W.

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A molecular dynamics simulation study of temperature and depth effect on helium bubble releasing from Ti surface

Cited by 10 publications

References 18 publications

Helium flux effects on bubble growth and surface morphology in plasma-facing tungsten from large-scale molecular dynamics simulations

Helium flux effects on bubble growth and surface morphology in plasma-facing tungsten from large-scale molecular dynamics simulations

Surface and internal microstructure damage of He-ion-irradiated CLAM steel studied by cross-sectional transmission electron microscopy

Review on helium behaviors in nanochannel tungsten film

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