{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/110846"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/110846","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Advanced characterization of the early-stage evolution of microstructures and mechanical properties in neutron-irradiated commercial steels","abstract":"In this project, the post-irradiation microstructures and mechanical properties of two types of Fe-Cr ferritic-martensitic (F-M) steels, HT9 and T91, were characterized. The materials were irradiated in the Advanced Test Reactor (ATR) at different temperatures and neutron fluences. Three temperature ranges and four neutron dose levels were investigated in this study. Utilizing transmission electron microscopy (TEM), atom probe tomography (APT) and energy dispersive X-ray spectroscopy (EDS), the nucleation, growth and stability of dislocation loops, G phase, α’ phase, and other precipitates were quantitatively analyzed. The irradiation hardening in these two materials were characterized using nanoindentation technique. The hardening behaviors were carefully analyzed against the observed microstructures using dispersed barrier hardening (DBH) model. In the irradiation conditions investigated in this study, the hardness evolution was dominated by the evolution of dislocation density at relatively high temperatures. Under low-temperature range (below 400°C), the hardening contribution mostly comes from the dispersed defect population. By comparing different irradiation conditions and materials, detailed evolution of microstructures and mechanical properties, and their dependence on Cr content were revealed. In general, it is found that the evolving pattern of microstructural defects and mechanical properties manifests significantly differently beyond certain threshold temperatures. This phenomenon appears to be highly correlated with the mobility of dislocation loops and dislocation lines. High mobility at high irradiation temperature disrupts the stability of the dislocation loop population, which results in decreasing internal sink strength and co-evolution with radiation-induced precipitates.","abstract_html":"In this project, the post-irradiation microstructures and mechanical properties of two types of Fe-Cr ferritic-martensitic (F-M) steels, HT9 and T91, were characterized. The materials were irradiated in the Advanced Test Reactor (ATR) at different temperatures and neutron fluences. Three temperature ranges and four neutron dose levels were investigated in this study. Utilizing transmission electron microscopy (TEM), atom probe tomography (APT) and energy dispersive X-ray spectroscopy (EDS), the nucleation, growth and stability of dislocation loops, G phase, α’ phase, and other precipitates were quantitatively analyzed. The irradiation hardening in these two materials were characterized using nanoindentation technique. The hardening behaviors were carefully analyzed against the observed microstructures using dispersed barrier hardening (DBH) model. In the irradiation conditions investigated in this study, the hardness evolution was dominated by the evolution of dislocation density at relatively high temperatures. Under low-temperature range (below 400°C), the hardening contribution mostly comes from the dispersed defect population. By comparing different irradiation conditions and materials, detailed evolution of microstructures and mechanical properties, and their dependence on Cr content were revealed. In general, it is found that the evolving pattern of microstructural defects and mechanical properties manifests significantly differently beyond certain threshold temperatures. This phenomenon appears to be highly correlated with the mobility of dislocation loops and dislocation lines. High mobility at high irradiation temperature disrupts the stability of the dislocation loop population, which results in decreasing internal sink strength and co-evolution with radiation-induced precipitates.","abstract_has_math":false,"creators":["Yan, Huan"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Nuclear, Plasma, Radiolgc Engr","degree_department":null,"school":null,"contributors":["Stubbins, James F.","Heuser, Brent J.","Trinkle, Dallas R.","Abbaszadeh, Shiva"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2021,"date_issued":"2021-09-17T04:04:47Z","date_published":"2021-09-17T04:04:47Z","updated_at":"2026-07-22T22:24:52Z","subjects":["Nuclear Materials","Ferritic Martensitic Steels","Neutron Irradiation","Transmission Electron Microscopy","Atom Probe Tomography","Irradiation Hardening"],"languages":["en"],"rights":["Copyright 2021 Huan Yan"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/110846","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Stubbins, James F.","Heuser, Brent J.","Trinkle, Dallas R.","Abbaszadeh, Shiva"]},{"key":"dc:creator","label":"Author","values":["Yan, Huan"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2021-09-17T04:04:47Z","2023-09-17T04:07:01Z","2021-04-21","2021-05"]},{"key":"dc:type","label":"Dc Type","values":["text","Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Nuclear, Plasma, Radiolgc 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":["Nuclear Materials","Ferritic Martensitic Steels","Neutron Irradiation","Transmission Electron Microscopy","Atom Probe Tomography","Irradiation Hardening"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2021 Huan Yan"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/110846"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["In this project, the post-irradiation microstructures and mechanical properties of two types of Fe-Cr ferritic-martensitic (F-M) steels, HT9 and T91, were characterized. The materials were irradiated in the Advanced Test Reactor (ATR) at different temperatures and neutron fluences. Three temperature ranges and four neutron dose levels were investigated in this study. Utilizing transmission electron microscopy (TEM), atom probe tomography (APT) and energy dispersive X-ray spectroscopy (EDS), the nucleation, growth and stability of dislocation loops, G phase, α’ phase, and other precipitates were quantitatively analyzed. The irradiation hardening in these two materials were characterized using nanoindentation technique. The hardening behaviors were carefully analyzed against the observed microstructures using dispersed barrier hardening (DBH) model. In the irradiation conditions investigated in this study, the hardness evolution was dominated by the evolution of dislocation density at relatively high temperatures. Under low-temperature range (below 400°C), the hardening contribution mostly comes from the dispersed defect population. By comparing different irradiation conditions and materials, detailed evolution of microstructures and mechanical properties, and their dependence on Cr content were revealed. In general, it is found that the evolving pattern of microstructural defects and mechanical properties manifests significantly differently beyond certain threshold temperatures. This phenomenon appears to be highly correlated with the mobility of dislocation loops and dislocation lines. High mobility at high irradiation temperature disrupts the stability of the dislocation loop population, which results in decreasing internal sink strength and co-evolution with radiation-induced precipitates.","Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2023-05-01","The student, Huan Yan, accepted the attached license on 2021-04-21 at 12:46.","The student, Huan Yan, submitted this Dissertation for approval on 2021-04-21 at 13:15.","This Dissertation was approved for publication on 2021-04-21 at 16:59.","DSpace SAF Submission Ingestion Package generated from Vireo submission #16466 on 2021-09-16 at 20:11:35","Made available in DSpace on 2021-09-17T04:04:47Z (GMT). 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The materials were irradiated in the Advanced Test Reactor (ATR) at different temperatures and neutron fluences. Three temperature ranges and four neutron dose levels were investigated in this study. Utilizing transmission electron microscopy (TEM), atom probe tomography (APT) and energy dispersive X-ray spectroscopy (EDS), the nucleation, growth and stability of dislocation loops, G phase, α’ phase, and other precipitates were quantitatively analyzed. The irradiation hardening in these two materials were characterized using nanoindentation technique. The hardening behaviors were carefully analyzed against the observed microstructures using dispersed barrier hardening (DBH) model. In the irradiation conditions investigated in this study, the hardness evolution was dominated by the evolution of dislocation density at relatively high temperatures. Under low-temperature range (below 400°C), the hardening contribution mostly comes from the dispersed defect population. By comparing different irradiation conditions and materials, detailed evolution of microstructures and mechanical properties, and their dependence on Cr content were revealed. In general, it is found that the evolving pattern of microstructural defects and mechanical properties manifests significantly differently beyond certain threshold temperatures. This phenomenon appears to be highly correlated with the mobility of dislocation loops and dislocation lines. High mobility at high irradiation temperature disrupts the stability of the dislocation loop population, which results in decreasing internal sink strength and co-evolution with radiation-induced precipitates.","Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2023-05-01","The student, Huan Yan, accepted the attached license on 2021-04-21 at 12:46.","The student, Huan Yan, submitted this Dissertation for approval on 2021-04-21 at 13:15.","This Dissertation was approved for publication on 2021-04-21 at 16:59.","DSpace SAF Submission Ingestion Package generated from Vireo submission #16466 on 2021-09-16 at 20:11:35","Made available in DSpace on 2021-09-17T04:04:47Z (GMT). No. of bitstreams: 3 YAN-DISSERTATION-2021.pdf: 491324743 bytes, checksum: 5faf8bd3745ae1e2dc9609cf2248ba69 (MD5) LICENSE.txt: 4205 bytes, checksum: f25352456df32b8a648615b1424743e4 (MD5) PROQUEST_LICENSE.txt: 4551 bytes, checksum: 86e28688eb94da3a7bdd44069cba59a7 (MD5) Previous issue date: 2021-04-21","Embargo set by: Seth Robbins for item 118691 Lift date: 2023-09-17T04:04:53Z Reason: Author requested closed access (OA after 2yrs) in Vireo ETD system","Embargo set by: Seth Robbins for item 118691 Lift date: 2023-09-17T04:07:01Z Reason: Author requested closed access (OA after 2yrs) in Vireo ETD system","Author requested closed access (OA after 2yrs) in Vireo ETD system","Limited"],"dc:format":["application/pdf"],"dc:identifier":["http://hdl.handle.net/2142/110846"],"dc:language":["en"],"dc:rights":["Copyright 2021 Huan Yan"],"dc:subject":["Nuclear Materials","Ferritic Martensitic Steels","Neutron Irradiation","Transmission Electron Microscopy","Atom Probe Tomography","Irradiation Hardening"],"dc:title":["Advanced characterization of the early-stage evolution of microstructures and mechanical properties in neutron-irradiated commercial steels"],"dc:type":["text","Thesis"],"thesis:degree_discipline":["Nuclear, Plasma, Radiolgc Engr"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:24:52Z"}