{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/25850"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/25850","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"The effect of high pressure on self-diffusion in beta-titanium","abstract":"\"Diffusion of Ti44 into beta-titanium has been measured as a function of pressure at approximately 10000C using standard lathe-sectioning techniques. The diffusion coefficient is found to decrease with pressure, indicating a positive activation volume. This result is in contradiction of earlier reports of negative activation volumes for diffusion of Fe in S-Ti and U in y-U. The value obtained for the activation volume for self-diffusion in S-Ti is approximately 3.6 ± 1.0 cm3/mOle, corresponding to ~V/VM = 0.33 + 0.1, where VM is the molar volume. Comparison is made with atomic.models and various proposed mechanisms for diffusion in the anomalous body-centered cubic metals. The magnitude of ~V appears to be too large to be consistent with the \"\"extrinsic\"\" vacancy mechanism of Kidson, but smaller than would normally be expected for simple vacancy diffusion in bcc metals; It is concluded that diffusion in beta-titanium most probably proceeds via a combination of vacancy and short dislocation-path diffusion, known as the Hart mechanism. Non-gaussian penetration profiles were observed in some of the runs. This has been interpreted in terms of oxide hold-up of the tracer at the surface and possible diffusion of the tracer as an oxide along dislocation pipes or grain boundaries near the surface prior to dissociation.\"","abstract_html":""Diffusion of Ti44 into beta-titanium has been measured as a function of pressure at approximately 10000C using standard lathe-sectioning techniques. The diffusion coefficient is found to decrease with pressure, indicating a positive activation volume. This result is in contradiction of earlier reports of negative activation volumes for diffusion of Fe in S-Ti and U in y-U. The value obtained for the activation volume for self-diffusion in S-Ti is approximately 3.6 ± 1.0 cm3/mOle, corresponding to ~V/VM = 0.33 + 0.1, where VM is the molar volume. Comparison is made with atomic.models and various proposed mechanisms for diffusion in the anomalous body-centered cubic metals. The magnitude of ~V appears to be too large to be consistent with the ""extrinsic"" vacancy mechanism of Kidson, but smaller than would normally be expected for simple vacancy diffusion in bcc metals; It is concluded that diffusion in beta-titanium most probably proceeds via a combination of vacancy and short dislocation-path diffusion, known as the Hart mechanism. Non-gaussian penetration profiles were observed in some of the runs. This has been interpreted in terms of oxide hold-up of the tracer at the surface and possible diffusion of the tracer as an oxide along dislocation pipes or grain boundaries near the surface prior to dissociation."","abstract_has_math":false,"creators":["Jeffery, Rondo Nelden"],"institution":null,"degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Physics","degree_department":null,"school":null,"contributors":["Lazarus, David"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":1970,"date_issued":"1970","date_published":"1970","updated_at":"2026-07-22T22:25:26Z","subjects":["high pressure","self-diffusion","beta-titanium","lathe-sectioning technique"],"languages":["en"],"rights":["1970 Rondo Nelden Jeffery"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["6053442"],"render_values":[{"text":"6053442","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/25850","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Lazarus, David"]},{"key":"dc:creator","label":"Author","values":["Jeffery, Rondo Nelden"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["1970","2011-07-26T20:20:12Z","10000-01-01"]},{"key":"dc:type","label":"Dc Type","values":["Dissertation / Thesis","text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Physics"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["high pressure","self-diffusion","beta-titanium","lathe-sectioning technique"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["1970 Rondo Nelden Jeffery"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["6053442","http://hdl.handle.net/2142/25850"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["\"Diffusion of Ti44 into beta-titanium has been measured as a function of pressure at approximately 10000C using standard lathe-sectioning techniques. The diffusion coefficient is found to decrease with pressure, indicating a positive activation volume. This result is in contradiction of earlier reports of negative activation volumes for diffusion of Fe in S-Ti and U in y-U. The value obtained for the activation volume for self-diffusion in S-Ti is approximately 3.6 ± 1.0 cm3/mOle, corresponding to ~V/VM = 0.33 + 0.1, where VM is the molar volume. Comparison is made with atomic.models and various proposed mechanisms for diffusion in the anomalous body-centered cubic metals. The magnitude of ~V appears to be too large to be consistent with the \"\"extrinsic\"\" vacancy mechanism of Kidson, but smaller than would normally be expected for simple vacancy diffusion in bcc metals; It is concluded that diffusion in beta-titanium most probably proceeds via a combination of vacancy and short dislocation-path diffusion, known as the Hart mechanism. Non-gaussian penetration profiles were observed in some of the runs. This has been interpreted in terms of oxide hold-up of the tracer at the surface and possible diffusion of the tracer as an oxide along dislocation pipes or grain boundaries near the surface prior to dissociation.\"","Submitted by Carolyn Mead (cmead2@illinois.edu) on 2011-07-26T20:20:12Z No. of bitstreams: 1 1970_jeffery.pdf: 2852702 bytes, checksum: fc1a5fea0d8b1f742fc3ef8f6b61bfdf (MD5)","Made available in DSpace on 2011-07-26T20:20:12Z (GMT). No. of bitstreams: 1 1970_jeffery.pdf: 2852702 bytes, checksum: fc1a5fea0d8b1f742fc3ef8f6b61bfdf (MD5) Previous issue date: 1970","Restriction data tranferred 2014-07-01T11:33:10-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: Thesis","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Carolyn Mead (cmead2@illinois.edu) on 2011-07-26T20:20:12Z Item is restricted indefinitely.","Thesis","U of I Only"]},{"key":"dc:title","label":"Title","values":["The effect of high pressure on self-diffusion in beta-titanium"]}]}],"canonical_facts":{"dc:contributor":["Lazarus, David"],"dc:creator":["Jeffery, Rondo Nelden"],"dc:date":["1970","2011-07-26T20:20:12Z","10000-01-01"],"dc:description":["\"Diffusion of Ti44 into beta-titanium has been measured as a function of pressure at approximately 10000C using standard lathe-sectioning techniques. The diffusion coefficient is found to decrease with pressure, indicating a positive activation volume. This result is in contradiction of earlier reports of negative activation volumes for diffusion of Fe in S-Ti and U in y-U. The value obtained for the activation volume for self-diffusion in S-Ti is approximately 3.6 ± 1.0 cm3/mOle, corresponding to ~V/VM = 0.33 + 0.1, where VM is the molar volume. Comparison is made with atomic.models and various proposed mechanisms for diffusion in the anomalous body-centered cubic metals. The magnitude of ~V appears to be too large to be consistent with the \"\"extrinsic\"\" vacancy mechanism of Kidson, but smaller than would normally be expected for simple vacancy diffusion in bcc metals; It is concluded that diffusion in beta-titanium most probably proceeds via a combination of vacancy and short dislocation-path diffusion, known as the Hart mechanism. Non-gaussian penetration profiles were observed in some of the runs. This has been interpreted in terms of oxide hold-up of the tracer at the surface and possible diffusion of the tracer as an oxide along dislocation pipes or grain boundaries near the surface prior to dissociation.\"","Submitted by Carolyn Mead (cmead2@illinois.edu) on 2011-07-26T20:20:12Z No. of bitstreams: 1 1970_jeffery.pdf: 2852702 bytes, checksum: fc1a5fea0d8b1f742fc3ef8f6b61bfdf (MD5)","Made available in DSpace on 2011-07-26T20:20:12Z (GMT). No. of bitstreams: 1 1970_jeffery.pdf: 2852702 bytes, checksum: fc1a5fea0d8b1f742fc3ef8f6b61bfdf (MD5) Previous issue date: 1970","Restriction data tranferred 2014-07-01T11:33:10-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: Thesis","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Carolyn Mead (cmead2@illinois.edu) on 2011-07-26T20:20:12Z Item is restricted indefinitely.","Thesis","U of I Only"],"dc:identifier":["6053442","http://hdl.handle.net/2142/25850"],"dc:language":["en"],"dc:rights":["1970 Rondo Nelden Jeffery"],"dc:subject":["high pressure","self-diffusion","beta-titanium","lathe-sectioning technique"],"dc:title":["The effect of high pressure on self-diffusion in beta-titanium"],"dc:type":["Dissertation / Thesis","text"],"thesis:degree_discipline":["Physics"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."]},"updated_at":"2026-07-22T22:25:26Z"}