Date of Final Oral Examination (Defense)
Type of Culminating Activity
Doctor of Philosophy in Materials Science and Engineering
Materials Science and Engineering
Janelle P. Wharry, Ph.D.
Hui Xiong, Ph.D.
Yaqiao Wu, Ph.D.
James Cole, Ph.D.
The objective of this study is to evaluate the mechanism of irradiation-induced nanoparticle evolution in a model Fe-9%Cr oxide dispersion strengthened steel and commercial ferritic-martensitic alloys HCM12A and HT9. Each alloy is irradiated with Fe2+ ions, protons, or neutrons to doses ranging from 1-100 displacements per atoms at 500°C. The morphology of nanoclusters are characterized using atom probe tomography. The evolution of clusters in each alloy are notably different with each irradiating particle, and the competing effects of ballistic dissolution and radiation-enhanced, diffusion-driven growth are attributed to the respective differences in cluster evolution. A phase evolution model, originally theorized by Nelson, Hudson, and Mazey, is used to simulate time-dependent nanocluster irradiation evolution in each alloy, with useful insights achieved to inform future alloy development. In all cases, a downward temperature shift is required to emulate low-dose-rate nanocluster evolution using higher-dose-rate irradiations.
Swenson, Matthew John, "The Mechanism of Radiation-Induced Nanocluster Evolution in Oxide Dispersion Strengthened and Ferritic-Martensitic Alloys" (2017). Boise State University Theses and Dissertations. 1319.