Properties of He clustering in α-Fe grain boundaries

Zhang, Lei; Fu, Chu‐Chun; Hayward, Erin; Lü, Guang-Hong

doi:10.1016/j.jnucmat.2015.01.008

Cited by 29 publications

(17 citation statements)

References 53 publications

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“…It has also been shown that He atoms aggregate in defects (point defect, grain boundary) to form bubbles in structural materials that result in void swelling and embrittlement [13,55,56]. Therefore, it is important to explore vacancy trapping mechanism for multiple He atoms inside RAFM steels.…”

Section: Vacancy Trapping For Multiple He In Presence Of Cr and Wmentioning

confidence: 99%

“…Inside the structural materials, He atom is mobile and easily to be trapped by point defects, forming He bubbles [10][11][12][13], leading to void swelling and He embrittlement. Thus, many attentions have been paid to investigate the behavior of single He impurity and He clusters in point defects and grain boundaries using first-principles calculations and molecular dynamics (MD) simulations [10][11][12][13][14][15][16][17][18][19], such as He solution and migration, formation of He-vacancy clusters, and He-to-vacancy ratio in bcc Fe. So far, most theoretical studies focused on He impurities in pure Fe solid.…”

Section: Introductionmentioning

confidence: 99%

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Effects of Cr and W additions on the stability and migration of He in bcc Fe: A first-principles study

Ding

et al. 2016

Computational Materials Science

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Section: Vacancy Trapping For Multiple He In Presence Of Cr and Wmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effects of Cr and W additions on the stability and migration of He in bcc Fe: A first-principles study

Ding

et al. 2016

Computational Materials Science

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“…In alloys, including alloys formed due to transmutation nuclear reactions [3], chemical segregation also occurs, resulting in the formation of helium bubbles [4][5][6], chromium or rhenium precipitates [7,8], and giving rise to grain boundary embrittlement [3,9]. Interpreting the observed microstructural evolution effects requires extending the measure of radiation damage beyond the displacement per atom (dpa) concept, proposed by Norgett et al [10] to quantify the exposure of materials to fluxes of energetic particles [11].…”

mentioning

confidence: 99%

Subcascade formation and defect cluster size scaling in high-energy collision events in metals

Backer¹,

Sand²,

Nordlund³

et al. 2016

EPL

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Az -Theory and Models of Radiation Effects PACS 61.82.Bg -Metals and Alloys PACS 61.72.J--Point Defects and Defect clustersAbstract -Recently, a scaling law describing the formation of defect clusters under irradiation has been established [1,2]. A critical constraint associated with its application to phenomena occurring over a broad range of irradiation conditions is the limitation on the energy of incident particles. Incident neutrons or ions, with energies exceeding a certain energy threshold, produce a complex hierarchy of collision subcascade events, which impedes the use of the defect cluster size scaling law derived for an individual low-energy cascade. By analyzing the statistics of subcascade sizes and energies, we show that defect clustering above threshold energies can be described by a product of two scaling laws, one for the sizes of subcascades and the other for the sizes of defect clusters formed in subcascades. The statistics of subcascade sizes exhibits a transition at a threshold energy, where the subcascade morphology changes from a single molten domain below the energy threshold, to several or many molten sub-domains above the threshold. The number of sub-domains then increases in proportion to the primary knock-on atom energy. The model has been validated against direct molecular dynamics simulations and applied to W, Fe, Be, Zr and sixteen other metals, enabling the prediction of full statistics of defect cluster sizes with no limitation on the energy of cascade events. We find that populations of defect clusters produced by the fragmented high-energy cascades are dominated by individual Frenkel pairs and relatively small defect clusters, whereas the lower-energy non-fragmented cascades produce a greater proportion of large defect clusters.

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“…Once a He atom segregates to a GB, its migration is greatly retarded [13,19]. However, He bubble growth at GBs in W has not received significant attention in the literature (although several studies of He bubbles in bcc Fe have been carried out [20][21][22][23][24][25][26]), which suggests that this important aspect of the effect of GBs in the evolution of He requires further study. This work, using accelerated molecular dynamics (AMD), begins to address this issue, with an emphasis on He irradiation rates appropriate for fusion-plasma conditions, thereby advancing our understanding of He evolution at GBs.…”

mentioning

confidence: 99%

New helium bubble growth mode at a symmetric grain-boundary in tungsten: accelerated molecular dynamics study

Liu

Uberuaga

Pérez

et al. 2018

Materials Research Letters

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This work, with an emphasis on helium irradiation rates appropriate for fusion-plasma conditions, advances the understanding of helium evolution at grain boundaries in W, an important consideration in the understanding of W as a plasma-facing component. Using accelerated molecular dynamics, helium bubble nucleation and growth at a symmetric 5[100](310) tilt grain-boundary in W is studied. The simulations reveal that the growth mode associated with bubble growth at the grain-boundary leads to a suppression of the helium supply to the bubble and hence to arrested growth. Such an unconventional bubble growth mode may dominate in materials with a high density of sinks. IMPACT STATEMENT Simulations of helium bubble nucleation and growth at a tungsten grain-boundary approaching helium-irradiation rates for fusion first-walls reveal a novel growth mode.

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Properties of He clustering in α-Fe grain boundaries

Cited by 29 publications

References 53 publications

Effects of Cr and W additions on the stability and migration of He in bcc Fe: A first-principles study

Effects of Cr and W additions on the stability and migration of He in bcc Fe: A first-principles study

Subcascade formation and defect cluster size scaling in high-energy collision events in metals

New helium bubble growth mode at a symmetric grain-boundary in tungsten: accelerated molecular dynamics study

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