Effects of vacancy-solute clusters on diffusivity in metastable Fe-C alloys
Diffusivity in defected crystals depends strongly on the interactions among vacancies and interstitials. Here we present atomistic analyses of point-defect cluster (PDC) concentrations and their kinetic barriers to diffusion in ferritic or body-centered-cubic (bcc) iron supersaturated with carbon. A...
| Main Authors: | , , , , |
|---|---|
| Other Authors: | |
| Format: | Article |
| Language: | en_US |
| Published: |
American Physical Society
2011
|
| Online Access: | http://hdl.handle.net/1721.1/60898 https://orcid.org/0000-0001-5735-0560 https://orcid.org/0000-0002-3230-280X https://orcid.org/0000-0002-2727-0137 |
| _version_ | 1810972535796269056 |
|---|---|
| author | Kabir, Mohammad Mukul Lau, Timothy T. Yip, Sidney Van Vliet, Krystyn J Lin, Xi, 1973- |
| author2 | Massachusetts Institute of Technology. Department of Materials Science and Engineering |
| author_facet | Massachusetts Institute of Technology. Department of Materials Science and Engineering Kabir, Mohammad Mukul Lau, Timothy T. Yip, Sidney Van Vliet, Krystyn J Lin, Xi, 1973- |
| author_sort | Kabir, Mohammad Mukul |
| collection | MIT |
| description | Diffusivity in defected crystals depends strongly on the interactions among vacancies and interstitials. Here we present atomistic analyses of point-defect cluster (PDC) concentrations and their kinetic barriers to diffusion in ferritic or body-centered-cubic (bcc) iron supersaturated with carbon. Among all possible point-defect species, only monovacancies, divacancies, and the PDC containing one vacancy and two carbon atoms are found to be statistically abundant. We find that the migration barriers of these vacancy-carbon PDCs are sufficiently high compared to that of monovacancies and divacancies. This leads to decreased self-diffusivity in bcc Fe with increasing carbon content for any given vacancy concentration, which becomes negligible when the local interstitial carbon concentration approaches twice that of free vacancies. These results contrast with trends observed in fcc Fe and provide a plausible explanation for the experimentally observed carbon dependence of volume diffusion-mediated creep in ferritic (bcc) Fe-C alloys. Moreover, this approach represents a general framework to predict self-diffusivity in alloys comprising a spectrum of point-defect clusters based on an energy-landscape survey of local energy minima (formation energies governing concentrations) and saddle points (activation barriers governing mobility). |
| first_indexed | 2024-09-23T07:53:15Z |
| format | Article |
| id | mit-1721.1/60898 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T07:53:15Z |
| publishDate | 2011 |
| publisher | American Physical Society |
| record_format | dspace |
| spelling | mit-1721.1/608982023-02-26T02:54:23Z Effects of vacancy-solute clusters on diffusivity in metastable Fe-C alloys Kabir, Mohammad Mukul Lau, Timothy T. Yip, Sidney Van Vliet, Krystyn J Lin, Xi, 1973- Massachusetts Institute of Technology. Department of Materials Science and Engineering Massachusetts Institute of Technology. Department of Nuclear Science and Engineering Van Vliet, Krystyn J. Van Vliet, Krystyn J. Kabir, Mohammad Mukul Lau, Timothy T. Yip, Sidney Diffusivity in defected crystals depends strongly on the interactions among vacancies and interstitials. Here we present atomistic analyses of point-defect cluster (PDC) concentrations and their kinetic barriers to diffusion in ferritic or body-centered-cubic (bcc) iron supersaturated with carbon. Among all possible point-defect species, only monovacancies, divacancies, and the PDC containing one vacancy and two carbon atoms are found to be statistically abundant. We find that the migration barriers of these vacancy-carbon PDCs are sufficiently high compared to that of monovacancies and divacancies. This leads to decreased self-diffusivity in bcc Fe with increasing carbon content for any given vacancy concentration, which becomes negligible when the local interstitial carbon concentration approaches twice that of free vacancies. These results contrast with trends observed in fcc Fe and provide a plausible explanation for the experimentally observed carbon dependence of volume diffusion-mediated creep in ferritic (bcc) Fe-C alloys. Moreover, this approach represents a general framework to predict self-diffusivity in alloys comprising a spectrum of point-defect clusters based on an energy-landscape survey of local energy minima (formation energies governing concentrations) and saddle points (activation barriers governing mobility). National Defense Science and Engineering Graduate Fellowship United States. Air Force Office of Scientific Research (PECASE program) 2011-02-04T15:58:32Z 2011-02-04T15:58:32Z 2010-10 2010-08 Article http://purl.org/eprint/type/JournalArticle 1098-0121 1550-235X http://hdl.handle.net/1721.1/60898 Kabir, Mukul et al. “Effects of vacancy-solute clusters on diffusivity in metastable Fe-C alloys.” Physical Review B 82.13 (2010): 134112. © 2010 The American Physical Society. https://orcid.org/0000-0001-5735-0560 https://orcid.org/0000-0002-3230-280X https://orcid.org/0000-0002-2727-0137 en_US http://dx.doi.org/10.1103/PhysRevB.82.134112 Physical Review B Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf American Physical Society APS |
| spellingShingle | Kabir, Mohammad Mukul Lau, Timothy T. Yip, Sidney Van Vliet, Krystyn J Lin, Xi, 1973- Effects of vacancy-solute clusters on diffusivity in metastable Fe-C alloys |
| title | Effects of vacancy-solute clusters on diffusivity in metastable Fe-C alloys |
| title_full | Effects of vacancy-solute clusters on diffusivity in metastable Fe-C alloys |
| title_fullStr | Effects of vacancy-solute clusters on diffusivity in metastable Fe-C alloys |
| title_full_unstemmed | Effects of vacancy-solute clusters on diffusivity in metastable Fe-C alloys |
| title_short | Effects of vacancy-solute clusters on diffusivity in metastable Fe-C alloys |
| title_sort | effects of vacancy solute clusters on diffusivity in metastable fe c alloys |
| url | http://hdl.handle.net/1721.1/60898 https://orcid.org/0000-0001-5735-0560 https://orcid.org/0000-0002-3230-280X https://orcid.org/0000-0002-2727-0137 |
| work_keys_str_mv | AT kabirmohammadmukul effectsofvacancysoluteclustersondiffusivityinmetastablefecalloys AT lautimothyt effectsofvacancysoluteclustersondiffusivityinmetastablefecalloys AT yipsidney effectsofvacancysoluteclustersondiffusivityinmetastablefecalloys AT vanvlietkrystynj effectsofvacancysoluteclustersondiffusivityinmetastablefecalloys AT linxi1973 effectsofvacancysoluteclustersondiffusivityinmetastablefecalloys |