{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/68649"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/68649","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Effect of Nonequilibrium Defects Due to Phase Transformation on Diffusion in Beta Zirconium","abstract":"The effect of the hcp(--->)bcc phase transformation on the anomalous diffusion characteristics of bcc zirconium has been investigated in this study. ('113)Sn and ('59)Fe tracers were used to typify the diffusing nature of self- and fast-diffusing atoms. A differential measurement of diffusion in two samples was carried out under very different preannealing conditions but otherwise identical states of diffusion time and temperature. In the first set of experiments, one of the samples was annealed for lengthy periods of time ((TURN) 20-30 hours) at premelting temperatures ((TURN) 1550(DEGREES)C) prior to diffusion (at lower temperature in the bcc phase). This was done in an attempt to decrease the defect concentration produced by the phase transformation. During the second set of experiments, the sample was cycled three times through the phase transformation temperature ((TURN) 890(DEGREES)C) (hcp(--->)bcc(--->)hcp(--->)bcc), with a view to enhance the defect density due to phase changes. In both sets of experiments, the second sample was raised to the diffusion temperature directly. The relative diffusivities of two samples were measured by serial sectioning and counting techniques. Appropriate correction methods were derived, for each set, to identify the proper interface because of the unique sectioning problems encountered.","abstract_html":"The effect of the hcp(--->)bcc phase transformation on the anomalous diffusion characteristics of bcc zirconium has been investigated in this study. ('113)Sn and ('59)Fe tracers were used to typify the diffusing nature of self- and fast-diffusing atoms. A differential measurement of diffusion in two samples was carried out under very different preannealing conditions but otherwise identical states of diffusion time and temperature. In the first set of experiments, one of the samples was annealed for lengthy periods of time ((TURN) 20-30 hours) at premelting temperatures ((TURN) 1550(DEGREES)C) prior to diffusion (at lower temperature in the bcc phase). This was done in an attempt to decrease the defect concentration produced by the phase transformation. During the second set of experiments, the sample was cycled three times through the phase transformation temperature ((TURN) 890(DEGREES)C) (hcp(--->)bcc(--->)hcp(--->)bcc), with a view to enhance the defect density due to phase changes. In both sets of experiments, the second sample was raised to the diffusion temperature directly. The relative diffusivities of two samples were measured by serial sectioning and counting techniques. Appropriate correction methods were derived, for each set, to identify the proper interface because of the unique sectioning problems encountered.","abstract_has_math":false,"creators":["Chelluri, Bhanumathi"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Metallurgical Engineering","degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2014,"date_issued":"2014-12-14T16:00:45Z","date_published":"2014-12-14T16:00:45Z","updated_at":"2026-07-22T22:25:59Z","subjects":["Engineering, Metallurgy"],"languages":["eng"],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["(UMI)AAI8114400"],"render_values":[{"text":"(UMI)AAI8114400","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/68649","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Chelluri, Bhanumathi"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2014-12-14T16:00:45Z","10000-01-01","1981"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Metallurgical Engineering"]},{"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":["Engineering, Metallurgy"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/68649","(UMI)AAI8114400"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["The effect of the hcp(--->)bcc phase transformation on the anomalous diffusion characteristics of bcc zirconium has been investigated in this study. ('113)Sn and ('59)Fe tracers were used to typify the diffusing nature of self- and fast-diffusing atoms. A differential measurement of diffusion in two samples was carried out under very different preannealing conditions but otherwise identical states of diffusion time and temperature. In the first set of experiments, one of the samples was annealed for lengthy periods of time ((TURN) 20-30 hours) at premelting temperatures ((TURN) 1550(DEGREES)C) prior to diffusion (at lower temperature in the bcc phase). This was done in an attempt to decrease the defect concentration produced by the phase transformation. During the second set of experiments, the sample was cycled three times through the phase transformation temperature ((TURN) 890(DEGREES)C) (hcp(--->)bcc(--->)hcp(--->)bcc), with a view to enhance the defect density due to phase changes. In both sets of experiments, the second sample was raised to the diffusion temperature directly. The relative diffusivities of two samples were measured by serial sectioning and counting techniques. Appropriate correction methods were derived, for each set, to identify the proper interface because of the unique sectioning problems encountered.","Within errors, no significant difference in diffusivity was found for ('113)Sn diffusion for differing preannealing conditions. A small difference of ((TURN) 30%) was found for ('59)Fe diffusion, but this result was somewhat obscured by the non-Gaussian tracer profiles measured for this case. The results show that the anomalous diffusion behavior of bcc zirconium is not a result of excess defects introduced by the hcp(--->)bcc phase transformation.","Made available in DSpace on 2014-12-14T16:00:45Z (GMT). No. of bitstreams: 1 8114400.pdf: 3145851 bytes, checksum: b1194c578ed6efe9589db8e5d53c38c3 (MD5) Previous issue date: 1981","Embargo set by: Seth Robbins for item 68827 Lift date: Forever Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs","Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs","U of I Only","121 p.","Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1981."]},{"key":"dc:title","label":"Title","values":["Effect of Nonequilibrium Defects Due to Phase Transformation on Diffusion in Beta Zirconium"]}]}],"canonical_facts":{"dc:creator":["Chelluri, Bhanumathi"],"dc:date":["2014-12-14T16:00:45Z","10000-01-01","1981"],"dc:description":["The effect of the hcp(--->)bcc phase transformation on the anomalous diffusion characteristics of bcc zirconium has been investigated in this study. ('113)Sn and ('59)Fe tracers were used to typify the diffusing nature of self- and fast-diffusing atoms. A differential measurement of diffusion in two samples was carried out under very different preannealing conditions but otherwise identical states of diffusion time and temperature. In the first set of experiments, one of the samples was annealed for lengthy periods of time ((TURN) 20-30 hours) at premelting temperatures ((TURN) 1550(DEGREES)C) prior to diffusion (at lower temperature in the bcc phase). This was done in an attempt to decrease the defect concentration produced by the phase transformation. During the second set of experiments, the sample was cycled three times through the phase transformation temperature ((TURN) 890(DEGREES)C) (hcp(--->)bcc(--->)hcp(--->)bcc), with a view to enhance the defect density due to phase changes. In both sets of experiments, the second sample was raised to the diffusion temperature directly. The relative diffusivities of two samples were measured by serial sectioning and counting techniques. Appropriate correction methods were derived, for each set, to identify the proper interface because of the unique sectioning problems encountered.","Within errors, no significant difference in diffusivity was found for ('113)Sn diffusion for differing preannealing conditions. A small difference of ((TURN) 30%) was found for ('59)Fe diffusion, but this result was somewhat obscured by the non-Gaussian tracer profiles measured for this case. The results show that the anomalous diffusion behavior of bcc zirconium is not a result of excess defects introduced by the hcp(--->)bcc phase transformation.","Made available in DSpace on 2014-12-14T16:00:45Z (GMT). No. of bitstreams: 1 8114400.pdf: 3145851 bytes, checksum: b1194c578ed6efe9589db8e5d53c38c3 (MD5) Previous issue date: 1981","Embargo set by: Seth Robbins for item 68827 Lift date: Forever Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs","Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs","U of I Only","121 p.","Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1981."],"dc:identifier":["http://hdl.handle.net/2142/68649","(UMI)AAI8114400"],"dc:language":["eng"],"dc:subject":["Engineering, Metallurgy"],"dc:title":["Effect of Nonequilibrium Defects Due to Phase Transformation on Diffusion in Beta Zirconium"],"dc:type":["text"],"thesis:degree_discipline":["Metallurgical Engineering"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:25:59Z"}