{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/101081"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/101081","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Microstructure evolution in Alloy 709 at 550 and 650 °C","abstract":"Alloy 709, a type of 20Cr-25Ni austenitic stainless steel is studied after thermal aging at 550°C and 650°C. The microstructure is characterized using variety of techniques. The alloy shows excellent thermal stability at its working temperature 550°C, while its microstructure evolves rapidly at 650°C with complex precipitation behaviors. NbX particles are of large amount in as-received material but partially dissolve during thermal aging, showing less stability compared to M23C6 at 650°C. A type of M6C’s variant is found after long-term aging and strongly correlated with M23C6, which could either be the result of a possible transition from M23C6 to M6C, or the dissolution of Nb(C, N). Small amount of Z phase are found to precipitate densely on dislocations and modify the dislocation structure after 3000 hours aging at 650◦C. The results are in good agreement with those of NF709 and further support the idea that the η structure can be stabilized by nitrogen.","abstract_html":"Alloy 709, a type of 20Cr-25Ni austenitic stainless steel is studied after thermal aging at 550°C and 650°C. The microstructure is characterized using variety of techniques. The alloy shows excellent thermal stability at its working temperature 550°C, while its microstructure evolves rapidly at 650°C with complex precipitation behaviors. NbX particles are of large amount in as-received material but partially dissolve during thermal aging, showing less stability compared to M23C6 at 650°C. A type of M6C’s variant is found after long-term aging and strongly correlated with M23C6, which could either be the result of a possible transition from M23C6 to M6C, or the dissolution of Nb(C, N). Small amount of Z phase are found to precipitate densely on dislocations and modify the dislocation structure after 3000 hours aging at 650◦C. The results are in good agreement with those of NF709 and further support the idea that the η structure can be stabilized by nitrogen.","abstract_has_math":false,"creators":["Yan, Huan"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"M.S.","degree_level":"Thesis","degree_discipline":"Nuclear, Plasma, Radiolgc Engr","degree_department":null,"school":null,"contributors":["Stubbins, James","Zhang, Yang"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2018,"date_issued":"2018-09-04T20:31:59Z","date_published":"2018-09-04T20:31:59Z","updated_at":"2026-07-22T22:24:38Z","subjects":["Austenitic Stainless Steel, Thermal Aging, Alloy 709"],"languages":["en"],"rights":["Copyright 2018 Huan Yan"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/101081","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Stubbins, James","Zhang, Yang"]},{"key":"dc:creator","label":"Author","values":["Yan, Huan"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2018-09-04T20:31:59Z","2018-04-26","2018-05"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Nuclear, Plasma, Radiolgc Engr"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Thesis"]},{"key":"thesis:degree_name","label":"Degree Name","values":["M.S."]},{"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":["Austenitic Stainless Steel, Thermal Aging, Alloy 709"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2018 Huan Yan"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/101081"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Alloy 709, a type of 20Cr-25Ni austenitic stainless steel is studied after thermal aging at 550°C and 650°C. The microstructure is characterized using variety of techniques. The alloy shows excellent thermal stability at its working temperature 550°C, while its microstructure evolves rapidly at 650°C with complex precipitation behaviors. NbX particles are of large amount in as-received material but partially dissolve during thermal aging, showing less stability compared to M23C6 at 650°C. A type of M6C’s variant is found after long-term aging and strongly correlated with M23C6, which could either be the result of a possible transition from M23C6 to M6C, or the dissolution of Nb(C, N). Small amount of Z phase are found to precipitate densely on dislocations and modify the dislocation structure after 3000 hours aging at 650◦C. The results are in good agreement with those of NF709 and further support the idea that the η structure can be stabilized by nitrogen.","Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2018-08-31 without embargo terms","The student, Huan Yan, accepted the attached license on 2018-04-25 at 15:08.","The student, Huan Yan, submitted this Thesis for approval on 2018-04-25 at 15:33.","This Thesis was approved for publication on 2018-04-26 at 09:46.","DSpace SAF Submission Ingestion Package generated from Vireo submission #12490 on 2018-08-31 at 17:14:49","Made available in DSpace on 2018-09-04T20:31:59Z (GMT). No. of bitstreams: 2 YAN-THESIS-2018.pdf: 33410784 bytes, checksum: 13126d3958816c65fc560f4a396e36c5 (MD5) LICENSE.txt: 4205 bytes, checksum: 52f66bb0c5dccbfe6490b133ccc06b64 (MD5) Previous issue date: 2018-04-26"]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Microstructure evolution in Alloy 709 at 550 and 650 °C"]}]}],"canonical_facts":{"dc:contributor":["Stubbins, James","Zhang, Yang"],"dc:creator":["Yan, Huan"],"dc:date":["2018-09-04T20:31:59Z","2018-04-26","2018-05"],"dc:description":["Alloy 709, a type of 20Cr-25Ni austenitic stainless steel is studied after thermal aging at 550°C and 650°C. The microstructure is characterized using variety of techniques. The alloy shows excellent thermal stability at its working temperature 550°C, while its microstructure evolves rapidly at 650°C with complex precipitation behaviors. NbX particles are of large amount in as-received material but partially dissolve during thermal aging, showing less stability compared to M23C6 at 650°C. A type of M6C’s variant is found after long-term aging and strongly correlated with M23C6, which could either be the result of a possible transition from M23C6 to M6C, or the dissolution of Nb(C, N). Small amount of Z phase are found to precipitate densely on dislocations and modify the dislocation structure after 3000 hours aging at 650◦C. The results are in good agreement with those of NF709 and further support the idea that the η structure can be stabilized by nitrogen.","Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2018-08-31 without embargo terms","The student, Huan Yan, accepted the attached license on 2018-04-25 at 15:08.","The student, Huan Yan, submitted this Thesis for approval on 2018-04-25 at 15:33.","This Thesis was approved for publication on 2018-04-26 at 09:46.","DSpace SAF Submission Ingestion Package generated from Vireo submission #12490 on 2018-08-31 at 17:14:49","Made available in DSpace on 2018-09-04T20:31:59Z (GMT). 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