{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/106307"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/106307","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Atomic scale diffusion in complex systems from first principles","abstract":"Transport of point defects controls a variety of materials process such as precipitation, segregation of solutes to grain boundaries and surfaces, and macroscopic properties such as corrosion resistance and ionic conductivity. Therefore, a quantitative prediction of atomic scale transport is crucial to development of new alloys. First principles calculations coupled with advanced diffusion models can accurately predict atomic scale transport mechanisms of point defects in solids. In this work, we examine transport of six solutes - Sn, Cr, Fe, Be, Al and Ni in HCP Zr, and the transport of oxygen vacancies in LaGaO$_3$. Zirconium alloys are used as nuclear fuel cladding materials for light water power reactors and understanding point defect diffusion in Zr will provide a step forward for developing oxidation tolerant alloys. We accurately model the vacancy metastable states observed in HCP Zr and for the first time examine the effect of these states on solute transport. Our results show that Sn and Al diffuse via vacancy mediated mechanism while Cr, Fe, Be and Ni diffuse via the interstitial mechanism at equilibrium. The drag ratios of Cr, Fe, Be and Ni are positive which suggests that non-equilibrium vacancy fluxes could drag these solutes. By combining interstitial and vacancy mediated diffusivities, we demonstrate that supersaturated vacancy concentrations slow down the interstitial diffusion while accelerating the vacancy mediated diffusion. In recent years, LaGaO$_3$ has attracted considerable interest for applications in solid oxide fuel due to high oxygen ion mobilities but the atomic scale diffusion mechanism of oxygen vacancies is not well understood. We examine the atomic scale migration of oxygen vacancies in LaGaO$_3$ and study the effect of strain on the diffusivities. We find that O vacancy diffusion is nearly isotropic in undoped LaGaO$_3$ and strains up to 2\\% can accelerate the diffusivity by two orders of magnitude which could help reduce operating temperatures of the fuel cells. Strong attractive Sr-vacancy and vacancy-vacancy interactions lead to formation of superbasins which trap the vacancy at lower concentrations. However, at sufficiently high concentrations, these superbasins could overlap and lead to fast diffusion via percolation.","abstract_html":"Transport of point defects controls a variety of materials process such as precipitation, segregation of solutes to grain boundaries and surfaces, and macroscopic properties such as corrosion resistance and ionic conductivity. Therefore, a quantitative prediction of atomic scale transport is crucial to development of new alloys. First principles calculations coupled with advanced diffusion models can accurately predict atomic scale transport mechanisms of point defects in solids. In this work, we examine transport of six solutes - Sn, Cr, Fe, Be, Al and Ni in HCP Zr, and the transport of oxygen vacancies in LaGaO<span class=\"etd-inline-math\"><sub>3</sub></span>. Zirconium alloys are used as nuclear fuel cladding materials for light water power reactors and understanding point defect diffusion in Zr will provide a step forward for developing oxidation tolerant alloys. We accurately model the vacancy metastable states observed in HCP Zr and for the first time examine the effect of these states on solute transport. Our results show that Sn and Al diffuse via vacancy mediated mechanism while Cr, Fe, Be and Ni diffuse via the interstitial mechanism at equilibrium. The drag ratios of Cr, Fe, Be and Ni are positive which suggests that non-equilibrium vacancy fluxes could drag these solutes. By combining interstitial and vacancy mediated diffusivities, we demonstrate that supersaturated vacancy concentrations slow down the interstitial diffusion while accelerating the vacancy mediated diffusion. In recent years, LaGaO<span class=\"etd-inline-math\"><sub>3</sub></span> has attracted considerable interest for applications in solid oxide fuel due to high oxygen ion mobilities but the atomic scale diffusion mechanism of oxygen vacancies is not well understood. We examine the atomic scale migration of oxygen vacancies in LaGaO<span class=\"etd-inline-math\"><sub>3</sub></span> and study the effect of strain on the diffusivities. We find that O vacancy diffusion is nearly isotropic in undoped LaGaO<span class=\"etd-inline-math\"><sub>3</sub></span> and strains up to 2\\% can accelerate the diffusivity by two orders of magnitude which could help reduce operating temperatures of the fuel cells. Strong attractive Sr-vacancy and vacancy-vacancy interactions lead to formation of superbasins which trap the vacancy at lower concentrations. However, at sufficiently high concentrations, these superbasins could overlap and lead to fast diffusion via percolation.","abstract_has_math":true,"creators":["Jain, Abhinav"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Materials Science & Engr","degree_department":null,"school":null,"contributors":["Trinkle, Dallas R","Bellon, Pascal","Perry, Nicola H","Ertekin, Elif"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2020,"date_issued":"2020-03-02T22:10:20Z","date_published":"2020-03-02T22:10:20Z","updated_at":"2026-07-22T22:24:45Z","subjects":["Diffusion","Zirconium","LSGM","Transport","Vacancy","Interstitial","DFT","First principles"],"languages":["en"],"rights":["Copyright 2019 Abhinav Jain"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/106307","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Trinkle, Dallas R","Bellon, Pascal","Perry, Nicola H","Ertekin, Elif"]},{"key":"dc:creator","label":"Author","values":["Jain, Abhinav"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2020-03-02T22:10:20Z","2022-03-03T10:15:19Z","2019-08-19","2019-12"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Materials Science & Engr"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Diffusion","Zirconium","LSGM","Transport","Vacancy","Interstitial","DFT","First principles"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2019 Abhinav Jain"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/106307"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Transport of point defects controls a variety of materials process such as precipitation, segregation of solutes to grain boundaries and surfaces, and macroscopic properties such as corrosion resistance and ionic conductivity. Therefore, a quantitative prediction of atomic scale transport is crucial to development of new alloys. First principles calculations coupled with advanced diffusion models can accurately predict atomic scale transport mechanisms of point defects in solids. In this work, we examine transport of six solutes - Sn, Cr, Fe, Be, Al and Ni in HCP Zr, and the transport of oxygen vacancies in LaGaO$_3$. Zirconium alloys are used as nuclear fuel cladding materials for light water power reactors and understanding point defect diffusion in Zr will provide a step forward for developing oxidation tolerant alloys. We accurately model the vacancy metastable states observed in HCP Zr and for the first time examine the effect of these states on solute transport. Our results show that Sn and Al diffuse via vacancy mediated mechanism while Cr, Fe, Be and Ni diffuse via the interstitial mechanism at equilibrium. The drag ratios of Cr, Fe, Be and Ni are positive which suggests that non-equilibrium vacancy fluxes could drag these solutes. By combining interstitial and vacancy mediated diffusivities, we demonstrate that supersaturated vacancy concentrations slow down the interstitial diffusion while accelerating the vacancy mediated diffusion. In recent years, LaGaO$_3$ has attracted considerable interest for applications in solid oxide fuel due to high oxygen ion mobilities but the atomic scale diffusion mechanism of oxygen vacancies is not well understood. We examine the atomic scale migration of oxygen vacancies in LaGaO$_3$ and study the effect of strain on the diffusivities. We find that O vacancy diffusion is nearly isotropic in undoped LaGaO$_3$ and strains up to 2\\% can accelerate the diffusivity by two orders of magnitude which could help reduce operating temperatures of the fuel cells. Strong attractive Sr-vacancy and vacancy-vacancy interactions lead to formation of superbasins which trap the vacancy at lower concentrations. However, at sufficiently high concentrations, these superbasins could overlap and lead to fast diffusion via percolation.","Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2021-12-01","The student, Abhinav Jain, accepted the attached license on 2019-08-14 at 21:02.","The student, Abhinav Jain, submitted this Dissertation for approval on 2019-08-14 at 22:04.","This Dissertation was approved for publication on 2019-08-19 at 14:03.","DSpace SAF Submission Ingestion Package generated from Vireo submission #14424 on 2020-02-28 at 17:20:00","Made available in DSpace on 2020-03-02T22:10:20Z (GMT). No. of bitstreams: 4 JAIN-DISSERTATION-2019.pdf: 13438877 bytes, checksum: c1e9186767f578e40febd4e71442e792 (MD5) Thesis.zip: 18643811 bytes, checksum: 17e93147a74ff976d48f08f4be535d58 (MD5) LICENSE.txt: 4209 bytes, checksum: 563ea7d222beea77e221f2dfe1d5c82c (MD5) PROQUEST_LICENSE.txt: 4555 bytes, checksum: 02194063ab0f428e943373f5d552abd4 (MD5) Previous issue date: 2019-08-19","Embargo set by: Seth Robbins for item 113847 Lift date: 2022-03-02T22:10:26Z Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD system","Embargo set by: Seth Robbins for item 113847 Lift date: 2022-03-02T22:11:40Z Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD system","Embargo set by: Seth Robbins for item 113847 Lift date: 2022-03-02T22:12:26Z Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD system","Embargo set by: Seth Robbins for item 113847 Lift date: 2022-03-02T22:15:21Z Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD system","Embargo set by: Seth Robbins for item 113847 Lift date: 2022-03-02T22:18:25Z Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD system","U of I Only Restriction Lifted for Item 113847 on 2022-03-03T10:15:19Z."]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Atomic scale diffusion in complex systems from first principles"]}]}],"canonical_facts":{"dc:contributor":["Trinkle, Dallas R","Bellon, Pascal","Perry, Nicola H","Ertekin, Elif"],"dc:creator":["Jain, Abhinav"],"dc:date":["2020-03-02T22:10:20Z","2022-03-03T10:15:19Z","2019-08-19","2019-12"],"dc:description":["Transport of point defects controls a variety of materials process such as precipitation, segregation of solutes to grain boundaries and surfaces, and macroscopic properties such as corrosion resistance and ionic conductivity. Therefore, a quantitative prediction of atomic scale transport is crucial to development of new alloys. First principles calculations coupled with advanced diffusion models can accurately predict atomic scale transport mechanisms of point defects in solids. In this work, we examine transport of six solutes - Sn, Cr, Fe, Be, Al and Ni in HCP Zr, and the transport of oxygen vacancies in LaGaO$_3$. Zirconium alloys are used as nuclear fuel cladding materials for light water power reactors and understanding point defect diffusion in Zr will provide a step forward for developing oxidation tolerant alloys. We accurately model the vacancy metastable states observed in HCP Zr and for the first time examine the effect of these states on solute transport. Our results show that Sn and Al diffuse via vacancy mediated mechanism while Cr, Fe, Be and Ni diffuse via the interstitial mechanism at equilibrium. The drag ratios of Cr, Fe, Be and Ni are positive which suggests that non-equilibrium vacancy fluxes could drag these solutes. By combining interstitial and vacancy mediated diffusivities, we demonstrate that supersaturated vacancy concentrations slow down the interstitial diffusion while accelerating the vacancy mediated diffusion. In recent years, LaGaO$_3$ has attracted considerable interest for applications in solid oxide fuel due to high oxygen ion mobilities but the atomic scale diffusion mechanism of oxygen vacancies is not well understood. We examine the atomic scale migration of oxygen vacancies in LaGaO$_3$ and study the effect of strain on the diffusivities. We find that O vacancy diffusion is nearly isotropic in undoped LaGaO$_3$ and strains up to 2\\% can accelerate the diffusivity by two orders of magnitude which could help reduce operating temperatures of the fuel cells. Strong attractive Sr-vacancy and vacancy-vacancy interactions lead to formation of superbasins which trap the vacancy at lower concentrations. However, at sufficiently high concentrations, these superbasins could overlap and lead to fast diffusion via percolation.","Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2021-12-01","The student, Abhinav Jain, accepted the attached license on 2019-08-14 at 21:02.","The student, Abhinav Jain, submitted this Dissertation for approval on 2019-08-14 at 22:04.","This Dissertation was approved for publication on 2019-08-19 at 14:03.","DSpace SAF Submission Ingestion Package generated from Vireo submission #14424 on 2020-02-28 at 17:20:00","Made available in DSpace on 2020-03-02T22:10:20Z (GMT). No. of bitstreams: 4 JAIN-DISSERTATION-2019.pdf: 13438877 bytes, checksum: c1e9186767f578e40febd4e71442e792 (MD5) Thesis.zip: 18643811 bytes, checksum: 17e93147a74ff976d48f08f4be535d58 (MD5) LICENSE.txt: 4209 bytes, checksum: 563ea7d222beea77e221f2dfe1d5c82c (MD5) PROQUEST_LICENSE.txt: 4555 bytes, checksum: 02194063ab0f428e943373f5d552abd4 (MD5) Previous issue date: 2019-08-19","Embargo set by: Seth Robbins for item 113847 Lift date: 2022-03-02T22:10:26Z Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD system","Embargo set by: Seth Robbins for item 113847 Lift date: 2022-03-02T22:11:40Z Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD system","Embargo set by: Seth Robbins for item 113847 Lift date: 2022-03-02T22:12:26Z Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD system","Embargo set by: Seth Robbins for item 113847 Lift date: 2022-03-02T22:15:21Z Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD system","Embargo set by: Seth Robbins for item 113847 Lift date: 2022-03-02T22:18:25Z Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD system","U of I Only Restriction Lifted for Item 113847 on 2022-03-03T10:15:19Z."],"dc:format":["application/pdf"],"dc:identifier":["http://hdl.handle.net/2142/106307"],"dc:language":["en"],"dc:rights":["Copyright 2019 Abhinav Jain"],"dc:subject":["Diffusion","Zirconium","LSGM","Transport","Vacancy","Interstitial","DFT","First principles"],"dc:title":["Atomic scale diffusion in complex systems from first principles"],"dc:type":["text"],"thesis:degree_discipline":["Materials Science & Engr"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:24:45Z"}