Electronic Structure Calculations of Oxygen Atom Transport Energetics in the Presence of Screw Dislocations in Tungsten
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...
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MDPI AG
2019-02-01
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| Online Access: | https://www.mdpi.com/2075-4701/9/2/252 |
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| author | Yue Zhao Lucile Dezerald Jaime Marian |
| author_facet | Yue Zhao Lucile Dezerald Jaime Marian |
| author_sort | Yue Zhao |
| collection | DOAJ |
| description | 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 <inline-formula> <math display="inline"> <semantics> <mrow> <mn>0.02</mn> </mrow> </semantics> </math> </inline-formula> and <inline-formula> <math display="inline"> <semantics> <mrow> <mn>0.02</mn> <msup> <mi>b</mi> <mn>3</mn> </msup> </mrow> </semantics> </math> </inline-formula>, 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. |
| first_indexed | 2024-12-20T11:35:56Z |
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| institution | Directory Open Access Journal |
| issn | 2075-4701 |
| language | English |
| last_indexed | 2024-12-20T11:35:56Z |
| publishDate | 2019-02-01 |
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| spelling | doaj.art-9065518c22064f0ab9d2ebdf0d024fdd2022-12-21T19:42:06ZengMDPI AGMetals2075-47012019-02-019225210.3390/met9020252met9020252Electronic Structure Calculations of Oxygen Atom Transport Energetics in the Presence of Screw Dislocations in TungstenYue Zhao0Lucile Dezerald1Jaime Marian2Department of Materials Science and Engineering, University of California Los Angeles, Los Angeles, CA 90095, USADepartment of Metallurgy, Materials Science and Engineering, Institut Jean Lamour, Université de Lorraine, Campus ARTEM, Allée André Guinier, F-54011 Nancy, FranceDepartment of Materials Science and Engineering, University of California Los Angeles, Los Angeles, CA 90095, USAPlastic 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 <inline-formula> <math display="inline"> <semantics> <mrow> <mn>0.02</mn> </mrow> </semantics> </math> </inline-formula> and <inline-formula> <math display="inline"> <semantics> <mrow> <mn>0.02</mn> <msup> <mi>b</mi> <mn>3</mn> </msup> </mrow> </semantics> </math> </inline-formula>, 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.https://www.mdpi.com/2075-4701/9/2/252W-O alloyinterstitial solid solutionscrew dislocationssolute diffusionstress coupling |
| spellingShingle | Yue Zhao Lucile Dezerald Jaime Marian Electronic Structure Calculations of Oxygen Atom Transport Energetics in the Presence of Screw Dislocations in Tungsten Metals W-O alloy interstitial solid solution screw dislocations solute diffusion stress coupling |
| title | Electronic Structure Calculations of Oxygen Atom Transport Energetics in the Presence of Screw Dislocations in Tungsten |
| title_full | Electronic Structure Calculations of Oxygen Atom Transport Energetics in the Presence of Screw Dislocations in Tungsten |
| title_fullStr | Electronic Structure Calculations of Oxygen Atom Transport Energetics in the Presence of Screw Dislocations in Tungsten |
| title_full_unstemmed | Electronic Structure Calculations of Oxygen Atom Transport Energetics in the Presence of Screw Dislocations in Tungsten |
| title_short | Electronic Structure Calculations of Oxygen Atom Transport Energetics in the Presence of Screw Dislocations in Tungsten |
| title_sort | electronic structure calculations of oxygen atom transport energetics in the presence of screw dislocations in tungsten |
| topic | W-O alloy interstitial solid solution screw dislocations solute diffusion stress coupling |
| url | https://www.mdpi.com/2075-4701/9/2/252 |
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