NSUF 26-5651: The Role of Temporal Temperature Gradients on Microstructure Evolution using Proton Irradiations
Nearly all neutron irradiation experiments for domestic materials qualification efforts are conducted in either the High Flux Isotope Reactor (HFIR) or the Advanced Test Reactor (ATR). Both facilities strongly utilize passive, non-instrumented insertions of sealed capsules containing materials of interest to expose them to radiation damage and elevated temperatures simultaneously. However, neither HFIR nor ATR run at “constant” conditions. Both facilities maintain total power per cycle, typically by slow removal of control elements, but this results in localized changes to the gamma flux and therefore in heat generation within the materials in the capsule and in irradiation temperature over the course of the cycle that passive temperature monitors may not capture. We propose to study the role of non-constant irradiation temperatures on the evolution of the microstructure using stainless steel as an example. Our hypothesis is that relative to a constant temperature ramping the temperature up with the same time-averaged temperature will increase the average dislocation loop diameter and lower the number density with an increase in the fraction of perfect dislocation loops to Frank loops. A decreasing irradiation temperature will have the opposite effect. Our approach includes tightly controlled proton irradiations with a feedback-controlled heating system to control the temperature following a pre-programmed pattern followed by post-irradiation microstructure characterization of dislocations loops and precipitates. The outcome of this work will provide fundamental information to determine mechanistic evolution of irradiated microstructures in non-constant temperatures and therefore, help to interpret the results of passive irradiation experiments performed in neutron environments.
Additional Info
| Field | Value |
|---|---|
| Awarded Institution | Oak Ridge National Laboratory |
| DOI | 10.46936/NSUF/60017662 |
| Embargo End Date | 2028-04-22 |
| Facility Tech Lead | Kevin Field, Kory Linton |
| Irradiation Facilities | Michigan Ion Beam Laboratory |
| NSUF Call | FY 2026 RTE 1st Call |
| PI | Stephen Taller |
| PIE Facilities | Low Activation Materials Design and Analysis Laboratory |
| Project Member | Dr. Kevin Field, Associate Professor - University of Michigan (https://orcid.org/0000-0002-3105-076X) |
| Project Member | Dr. Stephen Taller, R&D Staff Scientist - Oak Ridge National Laboratory (https://orcid.org/0000-0002-7323-4786) |
| Project Member | Dr. Richard Howard, Group Leader - Oak Ridge National Laboratory (https://orcid.org/0000-0002-8521-5427) |
| Project Member | Ms. Hannah Hutton, PhD Candidate - University of Michigan (https://orcid.org/0009-0003-4054-2576) |
| Project Member | Ms. Lauryn Kortman, Graduate Researcher - University of Michigan (https://orcid.org/0009-0003-6910-8992) |
| Project Type | RTE |