NSUF 26-5614: Mechanistic Insight into Mo-Induced ⟨100⟩ Loop Evolution in FeCrAl Alloys Using In-Situ Irradiations
FeCrAl alloys are leading candidates for accident-tolerant fuel cladding due to their superior oxidation resistance. However, the addition of Molybdenum (Mo) to enhance high-temperature strength has been shown in our preliminary ex-situ proton irradiation results to drastically increase the proportion and coalescence of sessile loops. Sessile loops are known to significantly impact the mechanical performance of FeCrAl alloys. This work seeks to validate our hypothesis that Mo-induced lattice strain alters point-defect transport, accelerating the transformation of glissile ½⟨111⟩ loops into embrittling sessile loops at elevated temperatures.
To investigate this mechanism, four alloy compositions (Fe-25Cr-6Al and Fe-12Cr-6Al, with and without Mo) will be studied using in-situ Transmission Electron Microscopy (TEM) ion irradiation at the Michigan Ion Beam Lab (MIBL). Experiments will be conducted at 400°C and 450°C using 1.1 MeV Kr3+ ions up to a dose of 5 dpa to capture observable microstructural evolution. TEM specimens will be prepared via EBSD-guided FIB lift-out near the [100] pole, coupled with flash-electropolishing to eliminate artifacts and ensure high-fidelity imaging. Dynamic processes such as loop motion, interaction, and coalescence will be quantified using machine learning-based detection frameworks, followed by post-irradiation examination (PIE) using inside-outside contrast analysis to identify loop nature. The successful completion of this research will provide a critical mechanistic understanding of the effects of Mo on dislocation loop formation in FeCrAl alloys, extending the material database and mechanistic insights for predictive modeling frameworks.
Additional Info
| Field | Value |
|---|---|
| Awarded Institution | University of Michigan |
| DOI | 10.46936/NSUF/60017672 |
| Embargo End Date | 2028-04-22 |
| Facility Tech Lead | Kevin Field |
| Irradiation Facilities | Michigan Ion Beam Laboratory |
| NSUF Call | FY 2026 RTE 1st Call |
| PI | Lingfeng Zhou |
| PIE Facilities | Michigan Ion Beam Laboratory, Michigan Center for Materials Characterization |
| Prep Facilities | Michigan Ion Beam Laboratory |
| Project Member | Dr. Kevin Field, Associate Professor - University of Michigan (https://orcid.org/0000-0002-3105-076X) |
| Project Member | Dr. Andrew Hoffman, Chief Innovation Officer - Catalyst Science Solutions (https://orcid.org/0000-0003-1915-2971) |
| Project Member | Dr. Yongfeng Zhang, Assistant Professor - University of Wisconsin (https://orcid.org/0000-0003-2730-3549) |
| Project Member | Mr. Lingfeng Zhou, Ph.D. Candidate - University of Michigan (https://orcid.org/0009-0008-8030-8027) |
| Project Member | Professor Wei Xiong, Associate Professor - University of Pittsburgh (https://orcid.org/0000-0002-3825-1679) |
| Project Member | Ms. Yuhan Li, Graduate Studen Research Assistant - University of Michigan-Ann Arbor (https://orcid.org/0009-0005-4677-0478) |
| Project Type | RTE |