Development and characterization of refractory high entropy alloys - evaluation of their mechanical properties and surface degradation behavior (Doctoral thesis)

Πούλια, Ανθούλα Β.


The present dissertation focuses on the development, characterization and evaluation of refractory high entropy alloys. These alloys are innovative materials which are targeted on applications of specialized requirements. The aim of the effort is to prepare single-phase and/or double phase structures and connect their microstructural features with their properties and degradation phenomena. More specifically, for each individual system produced, the microstructural characteristics were studied and the theoretical prediction models of solid solution formation, were checked. The corresponding solidification mechanisms were also studied, while their morphological characteristics were further analyzed. On the properties side, selected structures were studied as far as their mechanical properties (micro- and macro-hardness and compression tests) are concerned, while their strengthening mechanisms or failure modes were clarified. With regard to the alloys surface properties, the systems were examined in sliding wear tests under various experimental conditions. Through the recording of the numerical data and the study of the worn surfaces and debris, the corresponding wear mechanisms were formulated. Finally, the study of the corrosion behavior (solutions of 3.5 wt% NaCl and Hank) took place where, by analyzing the numerical data and the examination of the corroded surfaces / sections, the respective degradation mechanisms were interpreted.
Institution and School/Department of submitter: Πανεπιστήμιο Ιωαννίνων. Πολυτεχνική Σχολή. Τμήμα Μηχανικών Επιστήμης Υλικών
Subject classification: Κράματα (Μετάλλων)
Keywords: Κράματα υψηλής εντροπίας (HEAs),Μικροδομικός έλεγχος,Μηχανικές ιδιότητες,Φθορά ολίσθησης,Διάβρωση,High entropy alloys,Microstructural Investigation,Mechanical Properties,Sliding Wear,Corrosion
URI: http://olympias.lib.uoi.gr/jspui/handle/123456789/29222
Appears in Collections:Διδακτορικές Διατριβές

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