{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/45307"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/45307","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Defect mediated plasticity in Cu/Ag nanoscale multilayered metal composites: deformation twinning and wavy interface formation","abstract":"Made available in DSpace on 2013-08-22T16:35:38Z (GMT). No. of bitstreams: 4 Ruizhi_Li.pdf: 2616507 bytes, checksum: dff899bcd8bac69b54dbea75d994edac (MD5) 0_Li_Ruizhi.docx: 28848935 bytes, checksum: 4c460173b168128b9fb90f0828607c49 (MD5) Li_Ruizhi.docx: 28848935 bytes, checksum: 4c460173b168128b9fb90f0828607c49 (MD5) license.txt: 4056 bytes, checksum: 19f968ce7895acd28238d55fe2269aff (MD5)","abstract_html":"Made available in DSpace on 2013-08-22T16:35:38Z (GMT). No. of bitstreams: 4 Ruizhi_Li.pdf: 2616507 bytes, checksum: dff899bcd8bac69b54dbea75d994edac (MD5) 0_Li_Ruizhi.docx: 28848935 bytes, checksum: 4c460173b168128b9fb90f0828607c49 (MD5) Li_Ruizhi.docx: 28848935 bytes, checksum: 4c460173b168128b9fb90f0828607c49 (MD5) license.txt: 4056 bytes, checksum: 19f968ce7895acd28238d55fe2269aff (MD5)","abstract_has_math":false,"creators":["Li, Ruizhi"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"M.S.","degree_level":"Thesis","degree_discipline":"Aerospace Engineering","degree_department":null,"school":null,"contributors":["Chew, Huck Beng"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2013,"date_issued":"2013-08-22T16:35:38Z","date_published":"2013-08-22T16:35:38Z","updated_at":"2026-07-22T22:25:34Z","subjects":["Nanolayered metals","flaws","deformation twinning","interface migration","wavy interfaces","molecular dynamics"],"languages":["en"],"rights":["Copyright 2013 Ruizhi Li"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/45307","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Chew, Huck Beng"]},{"key":"dc:creator","label":"Author","values":["Li, Ruizhi"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2013-08-22T16:35:38Z","2013-08"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Aerospace Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Thesis"]},{"key":"thesis:degree_name","label":"Degree Name","values":["M.S."]},{"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":["Nanolayered metals","flaws","deformation twinning","interface migration","wavy interfaces","molecular dynamics"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2013 Ruizhi Li"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/45307"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Made available in DSpace on 2013-08-22T16:35:38Z (GMT). No. of bitstreams: 4 Ruizhi_Li.pdf: 2616507 bytes, checksum: dff899bcd8bac69b54dbea75d994edac (MD5) 0_Li_Ruizhi.docx: 28848935 bytes, checksum: 4c460173b168128b9fb90f0828607c49 (MD5) Li_Ruizhi.docx: 28848935 bytes, checksum: 4c460173b168128b9fb90f0828607c49 (MD5) license.txt: 4056 bytes, checksum: 19f968ce7895acd28238d55fe2269aff (MD5)","The exceptional mechanical properties of metallic nanolayers originate from the high density of nanoscale interfaces. However, conflicting observations in the relationship between mechanical properties and interlayer thicknesses, as well as discrepancies in measured strength between experiments and simulations, suggest that microstructural flaws play an essential role in the deformation behavior of actual metallic nanolayers. In this thesis, molecular dynamics simulations are used to uncover two distinct nanoscale plasticity mechanisms activated by the presence of micro-cracks and columnar grain boundaries in Cu/Ag nanolayers under tension. The first mechanism is deformation twinning, caused by emission of twinning partials from the micro-cracks and columnar grain boundaries. These deformation microtwins are transmitted across multiple Cu/Ag interlayers and facilitate the communication between spatially separated flaws. In addition, the intersections of microtwins on non-parallel slip planes produce formidable locks, which serve as stress concentration sites for incipient crack growth. The second mechanism is interlayer interface migration, which results in the morphological transition of initially planar Cu/Ag nanolayer to become wavy. This planar-to-wavy transition is driven by energetics, and is facilitated by dislocation climb along columnar grain boundaries. The above tensile-activated plasticity mechanisms are distinctly different from the strengthening mechanism associated with interface crossings of single dislocations under compression. Implications of these mechanisms to the ductility of metallic nanolayers, as well as the activation of novel nanoscale plastic recovery processes, are discussed.","Item withdrawn by Mark Zulauf (zulauf@illinois.edu) on 2013-07-18T18:16:12Z Item was in collections: University of Illinois Theses & Dissertations (ID: 1) No. of bitstreams: 6 Li_Ruizhi.pdf: 74639302 bytes, checksum: a39bffe36721eca8735122020464b89d (MD5) Li_Ruizhi.pdf: 74636428 bytes, checksum: 1248bd58c140f749de736d5d47e543ce (MD5) Li_Ruizhi.pdf: 74647197 bytes, checksum: a95b778f1955b3f74d0650108cbaeb34 (MD5) 0_Li_Ruizhi.docx: 28848935 bytes, checksum: 4c460173b168128b9fb90f0828607c49 (MD5) Li_Ruizhi.docx: 28848935 bytes, checksum: 4c460173b168128b9fb90f0828607c49 (MD5) Li_Ruizhi.pdf: 2616507 bytes, checksum: dff899bcd8bac69b54dbea75d994edac (MD5)"]},{"key":"dc:title","label":"Title","values":["Defect mediated plasticity in Cu/Ag nanoscale multilayered metal composites: deformation twinning and wavy interface formation"]}]}],"canonical_facts":{"dc:contributor":["Chew, Huck Beng"],"dc:creator":["Li, Ruizhi"],"dc:date":["2013-08-22T16:35:38Z","2013-08"],"dc:description":["Made available in DSpace on 2013-08-22T16:35:38Z (GMT). No. of bitstreams: 4 Ruizhi_Li.pdf: 2616507 bytes, checksum: dff899bcd8bac69b54dbea75d994edac (MD5) 0_Li_Ruizhi.docx: 28848935 bytes, checksum: 4c460173b168128b9fb90f0828607c49 (MD5) Li_Ruizhi.docx: 28848935 bytes, checksum: 4c460173b168128b9fb90f0828607c49 (MD5) license.txt: 4056 bytes, checksum: 19f968ce7895acd28238d55fe2269aff (MD5)","The exceptional mechanical properties of metallic nanolayers originate from the high density of nanoscale interfaces. However, conflicting observations in the relationship between mechanical properties and interlayer thicknesses, as well as discrepancies in measured strength between experiments and simulations, suggest that microstructural flaws play an essential role in the deformation behavior of actual metallic nanolayers. In this thesis, molecular dynamics simulations are used to uncover two distinct nanoscale plasticity mechanisms activated by the presence of micro-cracks and columnar grain boundaries in Cu/Ag nanolayers under tension. The first mechanism is deformation twinning, caused by emission of twinning partials from the micro-cracks and columnar grain boundaries. These deformation microtwins are transmitted across multiple Cu/Ag interlayers and facilitate the communication between spatially separated flaws. In addition, the intersections of microtwins on non-parallel slip planes produce formidable locks, which serve as stress concentration sites for incipient crack growth. The second mechanism is interlayer interface migration, which results in the morphological transition of initially planar Cu/Ag nanolayer to become wavy. This planar-to-wavy transition is driven by energetics, and is facilitated by dislocation climb along columnar grain boundaries. The above tensile-activated plasticity mechanisms are distinctly different from the strengthening mechanism associated with interface crossings of single dislocations under compression. Implications of these mechanisms to the ductility of metallic nanolayers, as well as the activation of novel nanoscale plastic recovery processes, are discussed.","Item withdrawn by Mark Zulauf (zulauf@illinois.edu) on 2013-07-18T18:16:12Z Item was in collections: University of Illinois Theses & Dissertations (ID: 1) No. of bitstreams: 6 Li_Ruizhi.pdf: 74639302 bytes, checksum: a39bffe36721eca8735122020464b89d (MD5) Li_Ruizhi.pdf: 74636428 bytes, checksum: 1248bd58c140f749de736d5d47e543ce (MD5) Li_Ruizhi.pdf: 74647197 bytes, checksum: a95b778f1955b3f74d0650108cbaeb34 (MD5) 0_Li_Ruizhi.docx: 28848935 bytes, checksum: 4c460173b168128b9fb90f0828607c49 (MD5) Li_Ruizhi.docx: 28848935 bytes, checksum: 4c460173b168128b9fb90f0828607c49 (MD5) Li_Ruizhi.pdf: 2616507 bytes, checksum: dff899bcd8bac69b54dbea75d994edac (MD5)"],"dc:identifier":["http://hdl.handle.net/2142/45307"],"dc:language":["en"],"dc:rights":["Copyright 2013 Ruizhi Li"],"dc:subject":["Nanolayered metals","flaws","deformation twinning","interface migration","wavy interfaces","molecular dynamics"],"dc:title":["Defect mediated plasticity in Cu/Ag nanoscale multilayered metal composites: deformation twinning and wavy interface formation"],"dc:type":["text"],"thesis:degree_discipline":["Aerospace Engineering"],"thesis:degree_level":["Thesis"],"thesis:degree_name":["M.S."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:25:34Z"}