{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/20226"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/20226","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Fatigue crack growth in polycrystalline alumina at high temperatures","abstract":"High temperature crack growth behavior in a commercial and a hot-pressed polycrystalline Al$\\sb2$O$\\sb3$ was examined under monotonic tensile loading (static fatigue) and under Mode-I tension-tension cyclic loading (cyclic fatigue). The investigation of fatigue crack growth in polycrystalline Al$\\sb2$O$\\sb3$ has confirmed the cyclic effect existing in ceramic materials, but this cyclic effect cannot be seen as the manifestation of static failure under cyclic loading. The temperature, load ratio, and microstructural factors, such as the grain boundary phase and grain size, play important roles in affecting high temperature crack growth behavior. Locally at the crack tip, the cyclic fatigue crack was found to advance in shear by the frictional sliding of grains on alternating sets of planes of the maximum shear. Evidence of shear-driven crack growth was supported by topological and morphological analyses of cyclic fatigue crack surface; grain sliding; frictional debris; and temperature-dependent of cyclic fatigue crack growth kinetics. Based on experimental observations, a new model of cyclic fatigue crack growth from alternating shears is proposed. The observed crack path morphology, the microstructure at the crack tip region, and the measured crack velocity under cyclic loading are distinctly different from those seen under static loading. At the crack tip, crack growth tends to follow the plane of the maximum tensile stress under static loading.","abstract_html":"High temperature crack growth behavior in a commercial and a hot-pressed polycrystalline Al$\\sb2$O$\\sb3$ was examined under monotonic tensile loading (static fatigue) and under Mode-I tension-tension cyclic loading (cyclic fatigue). The investigation of fatigue crack growth in polycrystalline Al$\\sb2$O$\\sb3$ has confirmed the cyclic effect existing in ceramic materials, but this cyclic effect cannot be seen as the manifestation of static failure under cyclic loading. The temperature, load ratio, and microstructural factors, such as the grain boundary phase and grain size, play important roles in affecting high temperature crack growth behavior. Locally at the crack tip, the cyclic fatigue crack was found to advance in shear by the frictional sliding of grains on alternating sets of planes of the maximum shear. Evidence of shear-driven crack growth was supported by topological and morphological analyses of cyclic fatigue crack surface; grain sliding; frictional debris; and temperature-dependent of cyclic fatigue crack growth kinetics. Based on experimental observations, a new model of cyclic fatigue crack growth from alternating shears is proposed. The observed crack path morphology, the microstructure at the crack tip region, and the measured crack velocity under cyclic loading are distinctly different from those seen under static loading. At the crack tip, crack growth tends to follow the plane of the maximum tensile stress under static loading.","abstract_has_math":true,"creators":["Huang, Ching-Hua"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Materials Science and Engineering","degree_department":null,"school":null,"contributors":["Shang, Jian Ku"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2011,"date_issued":"2011-05-07T12:32:53Z","date_published":"2011-05-07T12:32:53Z","updated_at":"2026-07-22T22:25:15Z","subjects":["Engineering, Materials Science"],"languages":["eng"],"rights":["Copyright 1995 Huang, Ching-Hua"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["AAI9624369","(UMI)AAI9624369"],"render_values":[{"text":"AAI9624369","href":null,"code":true},{"text":"(UMI)AAI9624369","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/20226","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Shang, Jian Ku"]},{"key":"dc:creator","label":"Author","values":["Huang, Ching-Hua"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2011-05-07T12:32:53Z","10000-01-01","1995"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Materials Science and 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, 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 Huang, Ching-Hua"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["AAI9624369","(UMI)AAI9624369","http://hdl.handle.net/2142/20226"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["High temperature crack growth behavior in a commercial and a hot-pressed polycrystalline Al$\\sb2$O$\\sb3$ was examined under monotonic tensile loading (static fatigue) and under Mode-I tension-tension cyclic loading (cyclic fatigue). The investigation of fatigue crack growth in polycrystalline Al$\\sb2$O$\\sb3$ has confirmed the cyclic effect existing in ceramic materials, but this cyclic effect cannot be seen as the manifestation of static failure under cyclic loading. The temperature, load ratio, and microstructural factors, such as the grain boundary phase and grain size, play important roles in affecting high temperature crack growth behavior. Locally at the crack tip, the cyclic fatigue crack was found to advance in shear by the frictional sliding of grains on alternating sets of planes of the maximum shear. Evidence of shear-driven crack growth was supported by topological and morphological analyses of cyclic fatigue crack surface; grain sliding; frictional debris; and temperature-dependent of cyclic fatigue crack growth kinetics. Based on experimental observations, a new model of cyclic fatigue crack growth from alternating shears is proposed. The observed crack path morphology, the microstructure at the crack tip region, and the measured crack velocity under cyclic loading are distinctly different from those seen under static loading. At the crack tip, crack growth tends to follow the plane of the maximum tensile stress under static loading.","Made available in DSpace on 2011-05-07T12:32:53Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9624369.pdf: 5099797 bytes, checksum: e8e353a6da1e9cc13ed6ed228e290053 (MD5) Previous issue date: 1995","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T14:42:28Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:18:28-05:00 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":["Fatigue crack growth in polycrystalline alumina at high temperatures"]}]}],"canonical_facts":{"dc:contributor":["Shang, Jian Ku"],"dc:creator":["Huang, Ching-Hua"],"dc:date":["2011-05-07T12:32:53Z","10000-01-01","1995"],"dc:description":["High temperature crack growth behavior in a commercial and a hot-pressed polycrystalline Al$\\sb2$O$\\sb3$ was examined under monotonic tensile loading (static fatigue) and under Mode-I tension-tension cyclic loading (cyclic fatigue). The investigation of fatigue crack growth in polycrystalline Al$\\sb2$O$\\sb3$ has confirmed the cyclic effect existing in ceramic materials, but this cyclic effect cannot be seen as the manifestation of static failure under cyclic loading. The temperature, load ratio, and microstructural factors, such as the grain boundary phase and grain size, play important roles in affecting high temperature crack growth behavior. Locally at the crack tip, the cyclic fatigue crack was found to advance in shear by the frictional sliding of grains on alternating sets of planes of the maximum shear. Evidence of shear-driven crack growth was supported by topological and morphological analyses of cyclic fatigue crack surface; grain sliding; frictional debris; and temperature-dependent of cyclic fatigue crack growth kinetics. Based on experimental observations, a new model of cyclic fatigue crack growth from alternating shears is proposed. The observed crack path morphology, the microstructure at the crack tip region, and the measured crack velocity under cyclic loading are distinctly different from those seen under static loading. At the crack tip, crack growth tends to follow the plane of the maximum tensile stress under static loading.","Made available in DSpace on 2011-05-07T12:32:53Z (GMT). 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