What is your thesis topic?
My thesis project focuses on dislocation loops created by ion irradiation in BCC Fe-Cr model alloys. The main characterization techniques to study these dislocation loops include state-of-the-art electron backscatter diffraction (EBSD), focused ion beam (FIB) sample preparation, energy dispersive x-ray spectroscopy (EDXS), atom probe tomography (APT), and transmission electron microscopy (TEM).
How is materials processing involved in your research?
To simulate the irradiation effects on the resulting microstructures and bulk properties of various structural materials used in a reactor, we varied the temperature and ion fluence during heavy ion beam. We took full advantage of the newly commissioned TEM Spectra 300 in the IAMM Core Microscopy Facility to study ion irradiated pure Fe, Fe-3Cr, Fe-5Cr, and Fe-8Cr alloys (wt% Cr). The effects of damage rate, damage level, temperature, and Cr concentration on dislocation loop formation were investigated.
Provide an example of where the material, process, or properties you are studying might find an application.
Ferritic-martensitic (FM) steels are extensively deployed in engineering systems, such as large-scale fossil and nuclear energy systems. However, FM steels face challenges including undesirably high irradiation-induced hardening and embrittlement at low to intermediate temperatures. These issues arise due to the abundant formation of dislocation loops and Cr-rich α’ precipitates. Although numerous experiments have been conducted on FM alloys over the past decades, the interpretation and quantification of these previous results were limited by the resolution of earlier scientific instruments. By applying multiple techniques, the dislocation loop formation mechanism(s) were tested. The damage level and damage rate effect on dislocation loop formation were explored, and a more comprehensive understanding of the physics revealed that these effects are imperative for designing next generation Fe-Cr based advanced alloys for extreme engineering environments. These results in turn will be used to improve the ion beam processing conditions on similar alloys in future.