Mobility of screw dislocation in BCC tungsten at high temperature in presence of carbon

Hachet, Guillaume; Caillard, D.; Ventelon, Lisa; Clouet, Emmanuel

doi:10.1016/j.actamat.2021.117440

Cited by 16 publications

(6 citation statements)

References 31 publications

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“…This boost may appear to contradict other simulation results on similar large interstitial-refractory systems (e.g. W-O, W-C) that generally show decreased mobility of screw dislocations by interstitials [12,42]. It may also seem to conflict with experimental reports of strengthening by O in Nb [10].…”

Section: Discussioncontrasting

confidence: 56%

“…This situation is essentially the R = 0 case in the present PFDD simulations. In this respect, the MD and PFDD results are consistent since the stress to move the screw dislocation is higher than σ 0 for an interstitial-free crystal [12]. Regarding experiments, due to their greater mobility relative to screw dislocations, edge dislocation behavior is usually ignored in bcc metals.…”

Section: Discussionmentioning

confidence: 59%

“…At low solute concentrations, these changes in mechanical properties are caused by dislocation interactions with interstitials dissolved in the lattice [11,12]. Interstitial atoms generate a distortion in the lattice that can interact with dislocation stress fields and create Cottrell atmospheres around the dislocation core and pin the dislocation in place [13,14].…”

Section: Introductionmentioning

confidence: 99%

“…Interstitials at the dislocation core can also alter the core structure and therefore the Peierls stress [17][18][19][20]. When a gliding dislocation intersects an interstitial atom, the dislocation may become pinned or cross-kinked [12,19]. Since interstitials C and O are relatively larger atoms, they generally cannot diffuse fast enough to keep up with gliding dislocations.…”

Section: Introductionmentioning

confidence: 99%

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Role of diffusing interstitials on dislocation glide in refractory body centered cubic metals

Fey,

Hunter,

Beyerlein

2024

Modelling Simul. Mater. Sci. Eng.

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In this work, we employ a phase field dislocation dynamics technique to simulate dislocation motion in body centered cubic refractory metals with diffusing interstitials. Two distinct systems are treated, Nb with O interstitials and W with H interstitials, to consider both relatively small and large atomic size interstitials. Simulations without and with driving stress are designed to investigate the role of interstitial type and mobility on the glide of edge- and screw-character dislocations. The simulations reveal the various short- and long-range dislocation–interstitial interactions that can take place and their dependency on interstitial type, site occupation, stress state, and mobility of the interstitials relative to dislocations. We show that while interstitial O increases the breakaway stress for both screw and edge dislocations in Nb, interstitial H in low H concentrations makes screw dislocations easier and the edge dislocations harder to move. The simulations find that screw dislocation glide is enhanced by the presence of interstitials in both systems. Edge dislocation glide is enhanced in W-H and inhibited in Nb-O.

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Section: Discussioncontrasting

confidence: 56%

Section: Discussionmentioning

confidence: 59%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Role of diffusing interstitials on dislocation glide in refractory body centered cubic metals

Fey,

Hunter,

Beyerlein

2024

Modelling Simul. Mater. Sci. Eng.

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show abstract

“…The dislocation core reconstruction induced by hydrogen segregation is however more complex as three different attractive sites per unit of Burgers vector are found for hydrogen in the dislocation core, instead of one unique attractive site for carbon. As already demonstrated with carbon in both Fe [57][58][59] and W [60] , this hydrogen segregation on screw dislocations is expected to have a strong impact on their glide motion. In particular, it should probably be necessary to consider that screw dislocations are gliding at low temperatures with their solute atmosphere, to understand the enhancement of screw dislocations mobility, which is seen experimentally [3,5] .…”

Section: Discussionmentioning

confidence: 53%