Direct evidence for helium bubble growth in molybdenum by the mechanism of loop punching

Evans, J.H.; Veen, A. van; Caspers, L.M.

doi:10.1016/0036-9748(81)90353-7

Cited by 78 publications

(15 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The main process of plastic deformation is controlled by formation of interstitials in the surrounding lattice, a mechanism that is called loop punching. In this mechanism, a bubble if over-pressurized, can produce its own vacancies by punching out a platelet of interstitial atoms thus producing an interstitial dislocation loop [3,41,42].…”

Section: Discussionmentioning

confidence: 99%

Molecular dynamics modeling of cavity strengthening in irradiated iron

Haghighat

Schaeublin

2007

J Computer-Aided Mater Des

View full text Add to dashboard Cite

One of the most important problems in the field of nuclear industry is the relationship between irradiation-induced damage and the resulting induced mechanical response of the target metal and in particular ferritic base steels. In this work molecular dynamics simulation is used to simulate the nanoscale interaction between a moving dislocation and a defect, such as a cavity, as void or He bubble. The stress-strain curves are obtained under imposed strain rate condition using the atomic potentials based on the Fe potential of Ackland et al. 1997 for a void and He bubble as a function of He content and temperature. It appears that a 2 nm void is a stronger obstacle than a He bubble at low He contents, whereas at high He contents, the He bubble becomes a stronger obstacle. With increasing temperature the escape stress decreases and at the same time there is increasing degeneracy in the type of interaction.

show abstract

Section: Discussionmentioning

confidence: 99%

Molecular dynamics modeling of cavity strengthening in irradiated iron

Haghighat

Schaeublin

2007

J Computer-Aided Mater Des

View full text Add to dashboard Cite

show abstract

“…a lattice vacancy) until such high pressures are obtained that loop punching can occur [15]. This is a pressure driven mechanism and typical pressures required for loop-punching are in the 5 GPa range for most metals [16].…”

Section: He Concentrations In W Fuzz Layersmentioning

confidence: 99%

Comparison of tungsten nano-tendrils grown in Alcator C-Mod and linear plasma devices

Wright¹,

Brunner²,

Baldwin³

et al. 2013

Journal of Nuclear Materials

View full text Add to dashboard Cite

Abstract:Growth of tungsten nano-tendrils ("fuzz") has been observed for the first time in the divertor region of a high-power density tokamak experiment. After 14 consecutive helium L-mode discharges in Alcator C-Mod, the tip of a tungsten Langmuir probe at the outer strike point was fully covered with a layer of nano-tendrils. The depth of the W fuzz layer (600 ± 150 nm) is consistent with an empirical growth formula from the PISCES experiment. Re-creating the C-Mod exposures as closely as possible in Pilot-PSI experiment can produce nearly-identical nano-tendril morphology and layer thickness at surface temperatures that agree with uncertainties with the C-Mod W probe temperature data. Helium concentrations in W fuzz layers are measured at 1-4 at.%, which is lower than expected for the observed sub-surface voids to be filled with several GPa of helium pressure. This possibly indicates that the void formation is not pressure driven.

show abstract

“…Each formation of one or more Frenkel pairs partially releases the pressure experienced by the bubble and increases the bubble size. As growth progresses, the corresponding interstitials aggregate into prismatic h111i dislocation loops that are ultimately emitted from the bubble to form adatom islands on the surface [35]. The process continues until the bubble comes within a few layers of the surface, at which point it bursts, creating a crater or a pinhole.…”

mentioning

confidence: 99%

Competing Kinetics and He Bubble Morphology in W

et al. 2015

View full text Add to dashboard Cite

The growth process of He bubbles in W is investigated using molecular dynamics and parallel replica dynamics for growth rates spanning 6 orders of magnitude. Fast and slow growth regimes are defined relative to typical diffusion hopping times of W interstitials around the He bubble. Slow growth rates allow the diffusion of interstitials around the bubble, favoring the biased growth of the bubble towards the surface. In contrast, at fast growth rates interstitials do not have time to diffuse around the bubble, leading to a more isotropic growth and increasing the surface damage.

show abstract

Direct evidence for helium bubble growth in molybdenum by the mechanism of loop punching

Cited by 78 publications

References 10 publications

Molecular dynamics modeling of cavity strengthening in irradiated iron

Molecular dynamics modeling of cavity strengthening in irradiated iron

Comparison of tungsten nano-tendrils grown in Alcator C-Mod and linear plasma devices

Competing Kinetics and He Bubble Morphology in W

Contact Info

Product

Resources

About