First-principles investigation on dissolution and diffusion of oxygen in tungsten

Alkhamees, Abdullah; Liu, Yuelin; Zhou, Hongbo; Jin, Shuo; Zhang, Ying; Lü, Guang-Hong

doi:10.1016/j.jnucmat.2009.07.012

Cited by 34 publications

(19 citation statements)

References 25 publications

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“…With this, we found solution energies of 1.01 eV and 0.70 eV for for octahedral and tetrahedral sites, respectively. While this is consistent with recent studies in W-O [41,42], it deviates from what was found in other bcc metals, where octahedral sites were more stable for interstitial impurities (this is consistent with an octahedral volume of V oct = a 3 0 /3, versus a tetrahedral one of V tet = a 3 0 /12) [26]. The reasons behind this behavior appear to be related to the overlap between the electron charge densities of O and W when the O atom is at a tetrahedral location [41].…”

Section: Oxygen Atom Stability In Bulk Tungstensupporting

confidence: 94%

“…The migration barrier, E m , between two neighboring tetrahedral sites was evaluated using the NEB method (refer to Section 2). For zero strain, we found a value of 0.20 eV for the migration energy of O in W, in good agreement with the 0.17 eV obtained by Alkhamees et al [41] and in contrast with values over 0.3 eV for octahedral→octahedral transitions by the same authors. This is also in concordance with both DFT and semi-empirical interatomic potential calculations of O migration in other bcc metals that consistently yielded larger values for the octahedral→octahedral jump [44][45][46].…”

Section: Oxygen Migration In Bulk Tungstensupporting

confidence: 92%

See 1 more Smart Citation

Electronic Structure Calculations of Oxygen Atom Transport Energetics in the Presence of Screw Dislocations in Tungsten

Zhao

Dézerald

Marian

2019

Metals

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Plastic flow in body-centered cubic (bcc) alloys is governed by the thermally-activated motion of screw dislocations in close-packed planes. In bcc interstitial solid solutions, solute diffusion can occur at very fast rates owing to low migration energies and solute concentrations. Under mechanical loading, solutes may move on the same or similar time scale as dislocations glide, even at low temperatures, potentially resulting in very rich co-evolution processes that may have important effects in the overall material response. It is therefore important to accurately quantify the coupling between interstitial impurities and dislocations, so that larger-scale models can correctly account for their interactions. In this paper, we use electronic structure calculations to obtain the energetics of oxygen diffusion under stress and its interaction energy with screw dislocation cores in bcc tungsten. We find that oxygen atoms preferentially migrate from tetrahedral to tetrahedral site with an energy of 0.2 eV. This energy couples only weakly to hydrostatic and deviatoric deformations, with activation volumes of less than 0.02 and 0.02 b 3 , respectively. The strongest effect is found for the inelastic interaction between O atoms and screw dislocation cores, which leads to attractive energies between 1.2 and 1.9 eV and sometimes triggers a transformation of the screw dislocation core from an easy core configuration to a hard core configuration.

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Section: Oxygen Atom Stability In Bulk Tungstensupporting

confidence: 94%

Section: Oxygen Migration In Bulk Tungstensupporting

confidence: 92%

Electronic Structure Calculations of Oxygen Atom Transport Energetics in the Presence of Screw Dislocations in Tungsten

Zhao

Dézerald

Marian

2019

Metals

View full text Add to dashboard Cite

show abstract

“…While this is consistent with recent studies in W-O [37], it deviates from what is commonly found for other bcc metals, where octahedral sites are more stable for interstitial impurities 1 [26,38]. The reasons behind this behavior appear to be related to the overlap of electron charge densities, which leads to a more stable bonding configuration when O is at a tetrahedral location [37]. Next, we study the dependence of H s with strain applied in the manner described in Sec.…”

Section: Oxygen Atom Stability In Bulk Tungstensupporting

confidence: 94%

“…2). In the absence of applied strain, we found a value of 0.20 eV for the migration energy of O in W, in good agreement with the 0.17 eV obtained by Alkhamees et al [37] and in contrast with values over 0.3 eV for octahedral→octahedral transitions by the same authors. This is also in concordance with both DFT and semi-empirical interatomic potential calculations of O migration in other bcc metals that consistently yield larger values for the octahedral→octahedral jump [42][43][44][45].…”

Section: Oxygen Migration In Bulk Tungstensupporting

confidence: 92%

Electronic Structure Calculations of Oxygen Atom Transport Energetics in the Presence of Screw Dislocations in Tungsten

Zhao¹,

Dézerald²,

Marian³

2019

Preprint

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Plastic flow in body-centered cubic (bcc) alloys is governed by the thermally-activated screw dislocation motion. In bcc interstitial solid solutions, solute diffusion can occur at very fast rates owing to low migration energies and solute concentrations. Under mechanical loading, solutes may move on the same or similar time scale as dislocations glide, even at low temperatures, potentially resulting in very rich co-evolution processes that may have important effects in the overall material response. It is therefore important to accurately quantify the coupling between interstitial impurities and dislocations, so that larger-scale models can correctly account for their (co)evolution. In this paper, we use electronic structure calculations to obtain the energetics of oxygen diffusion under stress and its interaction energy with screw dislocation cores in bcc tungsten. We find that oxygen atoms preferentially migrate from tetrahedral to tetrahedral sites with an energy of 0.2 eV. This energy couples only weakly to hydrostatic and deviatoric deformations, with activation volumes of less than $0.02$ and $0.2b^3$, respectively. The strongest effect is found for the inelastic interaction between O atoms and screw dislocation cores, which leads to attractive energies on the order of 1.5 eV and a structural transformation of the screw dislocation core from an `easy' to a `hard' core configuration

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“…Using ab initio calculations, Al Khamees et al . have shown that oxygen favors tetrahedral interstitial site (TIS) in α- W over octahedral interstitial site (OIS) 27 . Clustering of oxygen was also favorable in the neighboring TIS sites.…”

Section: Introductionmentioning

confidence: 99%

Unravelling oxygen driven α to β phase transformation in tungsten

Chattaraj

Balal

Yadav

et al. 2020

Sci Rep

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Thin films of β-W are the most interesting for manipulating magnetic moments using spin–orbit torques, and a clear understanding of α to β phase transition in W by doping impurity, especially oxygen, is needed. Here we present a combined experimental and theoretical study using grazing incidence X-ray diffraction, photoelectron spectroscopy, electron microscopy, and ab initio calculations to explore atomic structure, bonding, and oxygen content for understanding the formation of β-W. It is found that the W films on SiO2/Si have 13–22 at.% oxygen in A15 β structure. Ab initio calculations show higher solution energy of oxygen in β-W, and a tendency to transform locally from α to β phase with increasing oxygen concentration. X-ray absorption spectroscopy also revealed local geometry of oxygen in β-W, in agreement with the simulated one. These results offer an opportunity for a fundamental understanding of the structural transition in α-W and further development of β-W phase for device applications.

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First-principles investigation on dissolution and diffusion of oxygen in tungsten

Cited by 34 publications

References 25 publications

Electronic Structure Calculations of Oxygen Atom Transport Energetics in the Presence of Screw Dislocations in Tungsten

Electronic Structure Calculations of Oxygen Atom Transport Energetics in the Presence of Screw Dislocations in Tungsten

Electronic Structure Calculations of Oxygen Atom Transport Energetics in the Presence of Screw Dislocations in Tungsten

Unravelling oxygen driven α to β phase transformation in tungsten

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