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The preparation of bicrystal specimens of high interfacial purity and accurately controlled mismatch of orientation between grains with a specific boundary orientation are critical for fundamental studies of the structure and properties of grain boundaries. A method was developed for routinely producing high-purity aluminum bicrystals of desired mismatch and boundary orientation. A strain annealing technique was used for making large single crystals. The orientation, structural perfection, and chemical purity of the seeds were characterized, then the seeds were joined by using an electron beam welder. The welder was designed and built as a major portion of this work.

Ferritic chromium steels are important structural materials for future nuclear fission and fusion reactors due to their advantages over traditional austenitic steels, including low swelling rates, better thermal fatigue resistance, and lower thermal expansion coefficients. Radiation-induced segregation or depletion (RIS/RID) of solute atoms at grain boundaries is considered to be a potentially significant phenomenon for structural materials because of its potentially detrimental role in affecting microstructure and furthermore mechanical properties. However, the behaviour of Cr at grain boundaries in ferritic steels is not well understood. Both segregation and depletion of Cr at grain boundary under irradiation have been previously observed and no clear dependency on irradiation condition or alloy type has been presented. Furthermore, ferritic alloys are known to undergo hardening and embrittlement after thermal aging in the temperature range of 300-550DC and this phenomenon is related with a and a' phase separation occurring in the solid solution. However the low temperature a-a' miscibility gap in the currently used phase diagram is extrapolated from high temperature results and conflicts with many experimental observations. To understand the Cr behaviour at gram boundaries in ferritic steels under irradiation, a systematic approach combining SEM/EBSD, FIB specimen preparation and APT analysis has been developed and successfully applied to a Fe- 15.2at%Cr to investigate the effect of pre-irradiation chemistry, grain boundary misorientation, impurities, irradiation damage, irradiation depth, and other possible factors to get a better understanding of RIS/RID phenomena. Both low sigma boundaries and randomly selected high angle boundaries have been investigated in detail. Systematic differences between the behaviour of different classes of boundaries had been observed, and the operating mechanisms are also discussed in this thesis. The maximum separation method has been applied on APT data to study the C- enriched clusters and Cr-enriched clusters, which were not directly visible on the atom maps. The composition of the Cr-enriched clusters was consistent with a' phase and the irradiation was found to accelerate the nucleation rather than the growth of these clusters. Such results provided important information in re- determining the a-a' phase boundary.

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE. / Vita. / Includes bibliographical references. / by Joseph Michael Dynys. / Ph.D.

Thesis (Ph.D.)--Hong Kong University of Science and Technology, 2004. / Includes bibliographical references. Also available in electronic version. Access restricted to campus users.

Typescript. Includes vita and abstract. Includes bibliographical references (leaves 130-137). Abstract also available online in ProQuest, free to University of Oregon users.

Thesis (M. Sc.)--University of Alberta, 2010. / Title from pdf file main screen (viewed on July 15, 2010). A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Master of Science in Materials Engineering, Department of Chemical and Materials Engineering, University of Alberta. Includes bibliographical references.

Thesis (Ph.D.) - University of Queensland, 2003. / Includes bibliography.