{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/68645"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/68645","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Internal Hydrogen Embrittlement in the Aluminum - Zinc - Magnesium System","abstract":"153 p.","abstract_html":"153 p.","abstract_has_math":false,"creators":["Ciaraldi, Stephen William"],"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":"2014-12-14T16:00:44Z","date_published":"2014-12-14T16:00:44Z","updated_at":"2026-07-22T22:25:59Z","subjects":["Engineering, Metallurgy"],"languages":["eng"],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["(UMI)AAI8026469"],"render_values":[{"text":"(UMI)AAI8026469","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/68645","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Ciaraldi, Stephen William"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2014-12-14T16:00:44Z","10000-01-01","1980"]},{"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/2142/68645","(UMI)AAI8026469"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["153 p.","Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1980.","An investigation has been made of the internal hydrogen embrittlement of high strength aluminum alloys. The majority of experiments were performed using a high purity Al-5.5 wt pct Zn-2.5 wt pct Mg alloy hydrogenated to levels of up to 1 at pct either by mechanical polishing in aqueous solutions or by exposure to moist air. These specimens were observed to have reduced ductilities and fracture stresses during subsequent tensile tests in argon. Embrittlement was found to be reversible and could be suppressed by thermal treatments prior to testing. Strain rate was also found to influence the occurrence of embrittlement.","Severely embrittled specimens fractured intergranularly and a fragmented surface layer was often observed on the brittle grain boundary facets. Electron diffraction studies of the layer yielded polycrystalline patterns consistent with a hexagonal aluminum hydride, AlH(,3), with a = 2.90 (ANGSTROM) and c = 4.55 (ANGSTROM). This phase was observed to be unstable and patterns obtained from the fragmented layer after exposure to air were found to correspond to FCC aluminum. Transmission electron microscope and other studies revealed that the phase was not pre-existing prior to stressing. These results suggest that the mechanism of internal hydrogen embrittlement in the Al-Zn-Mg system involves the formation of stress induced hydrides.","Experiments were also performed using alloy 7075 and two high purity quaternary alloys of compositions, Al-6.16 wt pct Zn-2.23 wt pct Mg-1.55 wt pct Cu, and Al-6.29 wt pct Zn-2.40 wt pct Mg-2.53 wt pct Cu. Embrittlement was not obtained in the commercial 7075 alloy but both high purity quaternary alloys were susceptible to internal hydrogen embrittlement. A similar intergranular fragmented layer was also observed on the fracture surfaces of the high purity alloy having 2.53 wt pct Cu.","Made available in DSpace on 2014-12-14T16:00:44Z (GMT). No. of bitstreams: 1 8026469.pdf: 4153128 bytes, checksum: 7e328bca0a320efab9bc943112ce9629 (MD5) Previous issue date: 1980","Embargo set by: Seth Robbins for item 68823 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"]},{"key":"dc:title","label":"Title","values":["Internal Hydrogen Embrittlement in the Aluminum - Zinc - Magnesium System"]}]}],"canonical_facts":{"dc:creator":["Ciaraldi, Stephen William"],"dc:date":["2014-12-14T16:00:44Z","10000-01-01","1980"],"dc:description":["153 p.","Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1980.","An investigation has been made of the internal hydrogen embrittlement of high strength aluminum alloys. The majority of experiments were performed using a high purity Al-5.5 wt pct Zn-2.5 wt pct Mg alloy hydrogenated to levels of up to 1 at pct either by mechanical polishing in aqueous solutions or by exposure to moist air. These specimens were observed to have reduced ductilities and fracture stresses during subsequent tensile tests in argon. Embrittlement was found to be reversible and could be suppressed by thermal treatments prior to testing. Strain rate was also found to influence the occurrence of embrittlement.","Severely embrittled specimens fractured intergranularly and a fragmented surface layer was often observed on the brittle grain boundary facets. Electron diffraction studies of the layer yielded polycrystalline patterns consistent with a hexagonal aluminum hydride, AlH(,3), with a = 2.90 (ANGSTROM) and c = 4.55 (ANGSTROM). This phase was observed to be unstable and patterns obtained from the fragmented layer after exposure to air were found to correspond to FCC aluminum. Transmission electron microscope and other studies revealed that the phase was not pre-existing prior to stressing. These results suggest that the mechanism of internal hydrogen embrittlement in the Al-Zn-Mg system involves the formation of stress induced hydrides.","Experiments were also performed using alloy 7075 and two high purity quaternary alloys of compositions, Al-6.16 wt pct Zn-2.23 wt pct Mg-1.55 wt pct Cu, and Al-6.29 wt pct Zn-2.40 wt pct Mg-2.53 wt pct Cu. Embrittlement was not obtained in the commercial 7075 alloy but both high purity quaternary alloys were susceptible to internal hydrogen embrittlement. A similar intergranular fragmented layer was also observed on the fracture surfaces of the high purity alloy having 2.53 wt pct Cu.","Made available in DSpace on 2014-12-14T16:00:44Z (GMT). No. of bitstreams: 1 8026469.pdf: 4153128 bytes, checksum: 7e328bca0a320efab9bc943112ce9629 (MD5) Previous issue date: 1980","Embargo set by: Seth Robbins for item 68823 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"],"dc:identifier":["http://hdl.handle.net/2142/68645","(UMI)AAI8026469"],"dc:language":["eng"],"dc:subject":["Engineering, Metallurgy"],"dc:title":["Internal Hydrogen Embrittlement in the Aluminum - Zinc - Magnesium System"],"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"}