{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/23044"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/23044","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Plasma optical emission spectroscopy of laser cladding for process control and oxidation behavior of laser clad NbAl alloys","abstract":"Spectroscopic diagnostics based on the plasma optical emission spectroscopy has been employed in this investigation to infer composition, thickness, and temperature of the clad during laser cladding of Nb-Al-Hf alloys on Nb substrate. Isothermal oxidation behavior of the laser clad NbAl$\\sb3$ based alloys containing: up to 1.0 at. % B; 1.5 at. % Hf; and 3 or 6 at. % Ti has been investigated at 800$\\sp\\circ$C, 1200$\\sp\\circ$C, and 1400$\\sp\\circ$C.","abstract_html":"Spectroscopic diagnostics based on the plasma optical emission spectroscopy has been employed in this investigation to infer composition, thickness, and temperature of the clad during laser cladding of Nb-Al-Hf alloys on Nb substrate. Isothermal oxidation behavior of the laser clad NbAl$\\sb3$ based alloys containing: up to 1.0 at. % B; 1.5 at. % Hf; and 3 or 6 at. % Ti has been investigated at 800$\\sp\\circ$C, 1200$\\sp\\circ$C, and 1400$\\sp\\circ$C.","abstract_has_math":true,"creators":["Tewari, Sudhir Kumar"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Materials Science Engineering","degree_department":null,"school":null,"contributors":["Mazumder, Jyotirmoy"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2011,"date_issued":"2011-05-07T14:00:08Z","date_published":"2011-05-07T14:00:08Z","updated_at":"2026-07-22T22:25:21Z","subjects":["Engineering, Metallurgy","Engineering, Materials Science"],"languages":["eng"],"rights":["Copyright 1995 Tewari, Sudhir Kumar"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["9780591577839","AAI9807488","(UMI)AAI9807488"],"render_values":[{"text":"9780591577839","href":null,"code":true},{"text":"AAI9807488","href":null,"code":true},{"text":"(UMI)AAI9807488","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/23044","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Mazumder, Jyotirmoy"]},{"key":"dc:creator","label":"Author","values":["Tewari, Sudhir Kumar"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2011-05-07T14:00:08Z","10000-01-01","1995"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Materials Science 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","Engineering, Materials Science"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 1995 Tewari, Sudhir Kumar"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["9780591577839","AAI9807488","(UMI)AAI9807488","http://hdl.handle.net/2142/23044"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Spectroscopic diagnostics based on the plasma optical emission spectroscopy has been employed in this investigation to infer composition, thickness, and temperature of the clad during laser cladding of Nb-Al-Hf alloys on Nb substrate. Isothermal oxidation behavior of the laser clad NbAl$\\sb3$ based alloys containing: up to 1.0 at. % B; 1.5 at. % Hf; and 3 or 6 at. % Ti has been investigated at 800$\\sp\\circ$C, 1200$\\sp\\circ$C, and 1400$\\sp\\circ$C.","The results indicate that the intensity of the optical emission from plasma during laser cladding is affected by the variation in the thickness of the clad. Temperature of the clad is inversely proportional to clad thickness. Composition of the clad is affected by the local variation in the temperature of the clad. Both continuum and characteristic line emission may be used to monitor variation in clad thickness and laser power. Intensities of Nb-I and Hf-I lines are directly proportional and that of Al-II is inversely proportional to the thickness of the clad. The Nb-I/Al-II ratio and continuum intensities are directly proportional to laser power and to clad thickness. Nb-I/Al-II and Nb-I/Hf-I ratios increase, and Al-II/Hf-I ratio decreases, approximately linearly with increase in the concentration of Nb in the clad. The physical and chemical states of the alloying elements in the initial powder mixture and the constitution of the phase in the clad affect the correlation between the intensity ratio and composition.","The results indicate that the alloys containing Al-rich interdendritic phase form an outer layer exclusively of $\\alpha$-Al$\\rm\\sb2O\\sb3$ at all three test conditions irrespective of the alloying additions. Addition of Ti and/or presence of Al-rich interdendritic phase suppress the disintegration of NbAl$\\sb3$ at 800$\\sp\\circ$C caused by rapid oxidation along the grain boundaries known as 'pest phenomenon.' The oxidation resistance degrades as the fraction of Nb-rich phases (Al $<$ 75 at. %) in the alloys increases and a mixture of $\\alpha$-Al$\\rm\\sb2O\\sb3$ and NbAlO$\\sb4$ forms upon oxidation. Alternating layers of $\\alpha$-Al$\\rm\\sb2O\\sb3$ and NbAlO$\\sb4$ form at 1200$\\sp\\circ$C and 1400$\\sp\\circ$C only in NbAl$\\sb3$ + 3 at. % Ti alloy containing Nb-rich phases.","Made available in DSpace on 2011-05-07T14:00:08Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9807488.pdf: 11850337 bytes, checksum: 19c6ed5f6a8fd3717fb4b6b223bdc56e (MD5) Previous issue date: 1995","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T15:01:47Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:29:20-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission","ETDs are only available to UIUC Users without author permission","U of I Only"]},{"key":"dc:title","label":"Title","values":["Plasma optical emission spectroscopy of laser cladding for process control and oxidation behavior of laser clad NbAl alloys"]}]}],"canonical_facts":{"dc:contributor":["Mazumder, Jyotirmoy"],"dc:creator":["Tewari, Sudhir Kumar"],"dc:date":["2011-05-07T14:00:08Z","10000-01-01","1995"],"dc:description":["Spectroscopic diagnostics based on the plasma optical emission spectroscopy has been employed in this investigation to infer composition, thickness, and temperature of the clad during laser cladding of Nb-Al-Hf alloys on Nb substrate. Isothermal oxidation behavior of the laser clad NbAl$\\sb3$ based alloys containing: up to 1.0 at. % B; 1.5 at. % Hf; and 3 or 6 at. % Ti has been investigated at 800$\\sp\\circ$C, 1200$\\sp\\circ$C, and 1400$\\sp\\circ$C.","The results indicate that the intensity of the optical emission from plasma during laser cladding is affected by the variation in the thickness of the clad. Temperature of the clad is inversely proportional to clad thickness. Composition of the clad is affected by the local variation in the temperature of the clad. Both continuum and characteristic line emission may be used to monitor variation in clad thickness and laser power. Intensities of Nb-I and Hf-I lines are directly proportional and that of Al-II is inversely proportional to the thickness of the clad. The Nb-I/Al-II ratio and continuum intensities are directly proportional to laser power and to clad thickness. Nb-I/Al-II and Nb-I/Hf-I ratios increase, and Al-II/Hf-I ratio decreases, approximately linearly with increase in the concentration of Nb in the clad. The physical and chemical states of the alloying elements in the initial powder mixture and the constitution of the phase in the clad affect the correlation between the intensity ratio and composition.","The results indicate that the alloys containing Al-rich interdendritic phase form an outer layer exclusively of $\\alpha$-Al$\\rm\\sb2O\\sb3$ at all three test conditions irrespective of the alloying additions. Addition of Ti and/or presence of Al-rich interdendritic phase suppress the disintegration of NbAl$\\sb3$ at 800$\\sp\\circ$C caused by rapid oxidation along the grain boundaries known as 'pest phenomenon.' The oxidation resistance degrades as the fraction of Nb-rich phases (Al $<$ 75 at. %) in the alloys increases and a mixture of $\\alpha$-Al$\\rm\\sb2O\\sb3$ and NbAlO$\\sb4$ forms upon oxidation. Alternating layers of $\\alpha$-Al$\\rm\\sb2O\\sb3$ and NbAlO$\\sb4$ form at 1200$\\sp\\circ$C and 1400$\\sp\\circ$C only in NbAl$\\sb3$ + 3 at. % Ti alloy containing Nb-rich phases.","Made available in DSpace on 2011-05-07T14:00:08Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9807488.pdf: 11850337 bytes, checksum: 19c6ed5f6a8fd3717fb4b6b223bdc56e (MD5) Previous issue date: 1995","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T15:01:47Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:29:20-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission","ETDs are only available to UIUC Users without author permission","U of I Only"],"dc:identifier":["9780591577839","AAI9807488","(UMI)AAI9807488","http://hdl.handle.net/2142/23044"],"dc:language":["eng"],"dc:rights":["Copyright 1995 Tewari, Sudhir Kumar"],"dc:subject":["Engineering, Metallurgy","Engineering, Materials Science"],"dc:title":["Plasma optical emission spectroscopy of laser cladding for process control and oxidation behavior of laser clad NbAl alloys"],"dc:type":["text"],"thesis:degree_discipline":["Materials Science Engineering"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:25:21Z"}