{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/71805"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/71805","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Phase Transformations in Nearly Stoichiometric Nickel-Manganese Alloys","abstract":"The transformation behavior of Ni-Mn alloys in the vicinity of the equiatomic composition has been studied using transmission electron microscopy and diffraction, x-ray diffraction, optical microscopy, and electrical resistivity measurements. The transformation behavior was found to be markedly different comparing Mn-rich alloys and Ni-rich alloys. In Mn-rich alloys a martensitic transformation between the (beta) and (theta) phases takes place, while in Ni-rich alloys an order-disorder transformation between the (gamma) and (theta) phases takes place.","abstract_html":"The transformation behavior of Ni-Mn alloys in the vicinity of the equiatomic composition has been studied using transmission electron microscopy and diffraction, x-ray diffraction, optical microscopy, and electrical resistivity measurements. The transformation behavior was found to be markedly different comparing Mn-rich alloys and Ni-rich alloys. In Mn-rich alloys a martensitic transformation between the (beta) and (theta) phases takes place, while in Ni-rich alloys an order-disorder transformation between the (gamma) and (theta) phases takes place.","abstract_has_math":false,"creators":["Adachi, Kenji"],"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":"2014-12-16T20:51:53Z","date_published":"2014-12-16T20:51:53Z","updated_at":"2026-07-22T22:26:05Z","subjects":["Engineering, Metallurgy"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["(UMI)AAI8409854"],"render_values":[{"text":"(UMI)AAI8409854","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/71805","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Adachi, Kenji"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2014-12-16T20:51:53Z","10000-01-01","1983"]},{"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":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/71805","(UMI)AAI8409854"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["The transformation behavior of Ni-Mn alloys in the vicinity of the equiatomic composition has been studied using transmission electron microscopy and diffraction, x-ray diffraction, optical microscopy, and electrical resistivity measurements. The transformation behavior was found to be markedly different comparing Mn-rich alloys and Ni-rich alloys. In Mn-rich alloys a martensitic transformation between the (beta) and (theta) phases takes place, while in Ni-rich alloys an order-disorder transformation between the (gamma) and (theta) phases takes place.","The martensitic transformation proceeds both on quenching and on slow cooling from the (beta) region. However the martensite crystallography is nearly destroyed on slow cooling through a "tempering" process which involves the shrinkage of internal twins and the nucleation and growth of low-density twinned crystals along the variant-variant interfaces and grain boundaries.","The martensitic structural change, from L2(,o) (B2) to L1(,o), is the same as that for Ni-Al shape memory alloys. The A-D (fork) type, A-C (spear) type, and A-B (wedge) type combinations of thin-plate martensite, characteristic of thermoelastic alloys, have been identified using transmission electron microscopy, and the crystallography of the (theta) martensite has been found to agree very well with the predictions of the phenomenological crystallographic theory.","However, the Ni-Mn alloys were found to be extremely brittle and showed no memory-type deformation. This has been attributed to weak grain boundaries and matrix inclusions due to manganese oxidation, but crystallographic factors limiting the memory-type deformation enter in as well, which include mixed variant combinations other than the basic three types, numerous lattice defects within the martensite plates, and the large twinning shear magnitude. Possibilities of various different combinations of variants were also examined using the crystallographic theory and a complementary plate grouping has been suggested to be feasible for the self-accommodation of certain martensite variants.","Made available in DSpace on 2014-12-16T20:51:53Z (GMT). No. of bitstreams: 1 8409854.pdf: 6743550 bytes, checksum: b363bc53caae4696152005b315c97cb4 (MD5) Previous issue date: 1983","Embargo set by: Seth Robbins for item 71971 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","278 p.","Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1983."]},{"key":"dc:title","label":"Title","values":["Phase Transformations in Nearly Stoichiometric Nickel-Manganese Alloys"]}]}],"canonical_facts":{"dc:creator":["Adachi, Kenji"],"dc:date":["2014-12-16T20:51:53Z","10000-01-01","1983"],"dc:description":["The transformation behavior of Ni-Mn alloys in the vicinity of the equiatomic composition has been studied using transmission electron microscopy and diffraction, x-ray diffraction, optical microscopy, and electrical resistivity measurements. The transformation behavior was found to be markedly different comparing Mn-rich alloys and Ni-rich alloys. In Mn-rich alloys a martensitic transformation between the (beta) and (theta) phases takes place, while in Ni-rich alloys an order-disorder transformation between the (gamma) and (theta) phases takes place.","The martensitic transformation proceeds both on quenching and on slow cooling from the (beta) region. However the martensite crystallography is nearly destroyed on slow cooling through a "tempering" process which involves the shrinkage of internal twins and the nucleation and growth of low-density twinned crystals along the variant-variant interfaces and grain boundaries.","The martensitic structural change, from L2(,o) (B2) to L1(,o), is the same as that for Ni-Al shape memory alloys. The A-D (fork) type, A-C (spear) type, and A-B (wedge) type combinations of thin-plate martensite, characteristic of thermoelastic alloys, have been identified using transmission electron microscopy, and the crystallography of the (theta) martensite has been found to agree very well with the predictions of the phenomenological crystallographic theory.","However, the Ni-Mn alloys were found to be extremely brittle and showed no memory-type deformation. This has been attributed to weak grain boundaries and matrix inclusions due to manganese oxidation, but crystallographic factors limiting the memory-type deformation enter in as well, which include mixed variant combinations other than the basic three types, numerous lattice defects within the martensite plates, and the large twinning shear magnitude. Possibilities of various different combinations of variants were also examined using the crystallographic theory and a complementary plate grouping has been suggested to be feasible for the self-accommodation of certain martensite variants.","Made available in DSpace on 2014-12-16T20:51:53Z (GMT). No. of bitstreams: 1 8409854.pdf: 6743550 bytes, checksum: b363bc53caae4696152005b315c97cb4 (MD5) Previous issue date: 1983","Embargo set by: Seth Robbins for item 71971 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","278 p.","Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1983."],"dc:identifier":["http://hdl.handle.net/2142/71805","(UMI)AAI8409854"],"dc:subject":["Engineering, Metallurgy"],"dc:title":["Phase Transformations in Nearly Stoichiometric Nickel-Manganese Alloys"],"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":"2026-07-22T22:26:05Z"}