Doctoral Dissertations
Keywords and Phrases
Additive Manufacturing; Electron Microscopy; High-Entropy Alloys; High-Pressure Torsion; Microstructure Evolution; Precipitation Strengthening
Abstract
"High entropy alloys (HEAs) are a novel class of alloys made of multiple principal elements in near equal proportions. They have been observed to possess an array of useful engineering properties, such as good ductility and fracture toughness, high temperature strength, oxidation and corrosion resistance and irradiation resistance. This makes them promising candidates for harsh environments, especially nuclear reactors. These properties could potentially realize advanced Gen IV nuclear reactor designs. However, most HEA compositions contain Co, which activates under irradiation, generating safety and waste management concerns. This work studies three compositions of Co-free HEAs whose strength and microstructures are evaluated for high temperature irradiation resistance.
Although HEAs have often been studied for their tendency to form simple solid solutions, the resulting mechanical strength is often low. Introducing precipitates, grain boundaries and high dislocation densities can help increase the strength of HEAs at both room temperature and high temperatures. Many of these features will also serve as defect sinks under irradiation, further enhancing HEAs’ natural irradiation resistance. Thus, multiple fabrication methods were compared in this study to alter the alloy properties and microstructure, including traditional casting and aging, high pressure torsion (HPT) and additive manufacturing (AM). AM especially is likely to be employed in nuclear reactors due to the need for complex internal geometries. The effect of these different processing parameters and microstructures will allow the development of HEAs for different harsh environment applications"-- Abstract, p. iv
Advisor(s)
Wen, Haiming
Committee Member(s)
Hoffman, Andrew
Liou, Frank W.
Graham, Joseph T.
Newkirk, Joseph William
O'Malley, Ronald J.
Department(s)
Materials Science and Engineering
Degree Name
Ph. D. in Materials Science and Engineering
Publisher
Missouri University of Science and Technology
Publication Date
Spring 2025
Pagination
xix, 189 pages
Note about bibliography
Includes_bibliographical_references_(pages 53, 89, 128, 167 and 178-187)
Rights
©2024 Matthew John Luebbe , All Rights Reserved
Document Type
Dissertation - Open Access
File Type
text
Language
English
Thesis Number
T 12463
Recommended Citation
Luebbe, Matthew John, "Development And Testing Of Irradiation-Tolerant High-Entropy Alloys" (2025). Doctoral Dissertations. 3377.
https://scholarsmine.mst.edu/doctoral_dissertations/3377
