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dc.contributor.authorZhang, He
dc.contributor.otherQueen's University (Kingston, Ont.). Theses (Queen's University (Kingston, Ont.))en
dc.date2013-09-05 18:28:04.382en
dc.date2013-09-06 15:21:02.334en
dc.date.accessioned2013-09-10T19:26:36Z
dc.date.available2013-09-10T19:26:36Z
dc.date.issued2013-09-10
dc.identifier.urihttp://hdl.handle.net/1974/8264
dc.descriptionThesis (Ph.D, Mechanical and Materials Engineering) -- Queen's University, 2013-09-06 15:21:02.334en
dc.description.abstractInconel alloys are commonly used as structural materials in nuclear reactors. One of these alloys, the Inconel X-750, is a γ’ Ni3(Al, Ti) strengthened superalloy extensively used in the cores of reactors, such as spacers in CANada Deuterium Uranium (CANDU) fuel channels. Prior to their application in commercial reactors, accelerated irradiation tests had been conducted in liquid metal fast reactors. Results did not indicate any problem stemming from significant fast neutron irradiation. However, recently it has been found that the ex-service CANDU Inconel X-750 spacers became severely brittle after a lengthy exposure to reactor environment. The underlying mechanism remains unclear and thus forms the focus of this current investigation, predominantly through transmission electron microscopy (TEM). This dissertation unfolds with the literature review in Chapter 2, followed by presentation of novel techniques in Chapter 3 on the preparation of TEM samples from small reactor components, namely the spacers. Chapter 4 presents TEM characterizations of ex-service spacers removed from the reactors. To simulate neutron irradiation over wide temperature range in an effort to understand the damage mechanisms, heavy ion irradiations were conducted and reported in Chapter 5 and 6. Irradiations are found to significantly alter the stability of the primary strengthening phase γ’, a systematic experimental study of which is presented in Chapter 7. To fully understand the effects of transmutation produced helium on irradiation induced cavity and dislocation microstructures, TEM in-situ heavy ion irradiations with hot/cold pre-injected helium were conducted and reported in Chapter 8 and 9. Helium was found to play an important role in the irradiation-induced instability of γ’ in nickel-based superalloys, the discussion of which is presented in Chapter 10. As one of the most important defect structures induced from irradiation, the stacking-fault-tetrahedra, were dynamically observed and are described in a journal manuscript in Appendix A. In addition to broadening current understanding of material degradation mechanism for in-service CANDU spacer, this study also provides comprehensive information on irradiation damage in nickel based superalloys, irradiation induced lattice defects and phase instability in face centered cubic alloys, as well as helium’s effects on cavity formation, dislocation evolution, and phase transformation.en_US
dc.languageenen
dc.language.isoenen_US
dc.relation.ispartofseriesCanadian thesesen
dc.rightsThis publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.en
dc.subjectDisorderingen_US
dc.subjectCANDUen_US
dc.subjectHeliumen_US
dc.subjectInconel X-750en_US
dc.subjectDamageen_US
dc.subjectRadiationen_US
dc.subjectCavityen_US
dc.subjectSFTen_US
dc.subjectSpaceren_US
dc.subjectTEMen_US
dc.titleIrradiation induced damage in CANDU spacer material Inconel X-750en_US
dc.typethesisen_US
dc.description.degreePh.Den
dc.contributor.supervisorYao, Zhongwenen
dc.contributor.departmentMechanical and Materials Engineeringen


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