NSUF 14-486: Irradiation-induced segregation, phase stability, and microstructure in 8-10 wt% Cr ODS alloys
Oxide-dispersion strengthened (ODS) ferritic-martensitic (F-M) alloys are leading candidates for structural components in fusion and fast fission reactors, because of their high-temperature strength, dimensional stability, and low activation. The large number of interfaces in F-M ODS alloys serve as point defect sinks, limiting the concentration of vacancies available to coalesce into bubbles or voids, thus increasing the radiation resistance of these materials. However, a high density of interfaces could be adverse to radiation tolerance if considerable radiation-induced segregation (RIS) were to occur at the interfaces. Lower-Cr F-M ODS alloys (i.e. those steels containing ~8-10 wt% Cr in bulk) could be attractive for nuclear applications because brittle, Cr-rich a’ phases have only been observed in higher-Cr F-M alloys. But on the other hand, the extent of Cr enrichment at grain boundaries is greater in the lower-Cr F-M alloys than in the higher-Cr F-M alloys. Recent studies on the irradiation response of F-M ODS alloys to have focused almost exclusively on higher-Cr ODS steels such as MA957 and 14YWT (both ~14 wt% Cr). Only limited work has been published on the irradiation response of the lower-Cr F-M ODS alloys. This project aims to characterize the irradiation response of lower-Cr F-M ODS alloys, including the phase stability, evolution of the oxide dispersoids, microstructure, and RIS. The specimens to be studied are a model Fe-9Cr ODS alloy and 9YWT, each previously irradiated with 5.0 MeV Fe++ ions to 100 dpa at 400°C. A sample of the same heat of the Fe-9Cr ODS alloy (sample library #023-331), which has been irradiated in the Advanced Test Reactor to 3 dpa at 500°C, will also be characterized. This project presents a rare opportunity to compare irradiation effects in the Fe-9Cr ODS alloy across two dose rates, without being affected by heat-to-heat variability. A combination of transmission electron microscopy (TEM) and local electrode atom probe (LEAP) analyses will provide a thorough characterization of the irradiated microstructure, phases, and grain boundary RIS. This proposal requests access to the Microscopy and Characterization Suite (MaCS) at the Center for Advanced Energy Studies (CAES), for 6 days on the FEI Quanta focused ion beam, 4 days on the CAMECA 4000X HR LEAP, and 6 days on the FEI Tecnai TEM.
Additional Info
| Field | Value |
|---|---|
| Awarded Institution | Boise State University |
| Embargo End Date | 2026-02-27 |
| Facility Tech Lead | Mukesh Bachhav |
| NSUF Call | FY 2014 RTE 2nd Call |
| PI | Janelle Wharry |
| Project Member | Professor Matthew Swenson, Associate Professor - University of Idaho (https://orcid.org/0000-0001-6163-3897) |
| Project Member | Professor Janelle Wharry, Professor - University of Illinois (https://orcid.org/0000-0001-7791-4394) |
| Project Type | RTE |
| Publication | TEM characterization of irradiated microstructure of Fe-9%Cr ODS and ferritic-martensitic alloys Matthew Swenson, Janelle Wharry Journal of Nuclear Materials 502 2018-04-15 https://www.sciencedirect.com/science/article/pii/S0022311517313910 |
| Publication | Plastic zone size for nanoindentation of irradiated Fe-9wt% Cr ODS alloy Janelle Wharry, Corey Dolph, Matthew Swenson Journal of Nuclear Materials 481 2016-11-01 https://www.sciencedirect.com/science/article/pii/S0022311516306559#ack0010 |
| Publication | Correlation between the microstructure and mechanical properties of irradiated Fe-9Cr ODS Corey Dolph, Matthew Swenson, Janelle Wharry Transactions of the American Nuclear Society 110 2014-01-01 http://scholarworks.boisestate.edu/cgi/viewcontent.cgi?article=1218&context=mse_facpubs&sei-redir=1&referer=http%3A%2F%2Fwww.bing.com%2Fsearch%3Fq%3DCorrelation%2Bbetween%2Bthe%2Bmicrostructure%2Band%2Bmechanical%2Bproperties%2Bof%2Birradiated%2BFe-9Cr%2BODS%26src%3Die9tr#search=%22Correlation%20between%20microstructure%20mechanical%20properties%20irradiated%20Fe-9Cr%20ODS%22 |
| Publication | Collected data set size considerations for atom probe cluster analysis Janelle Wharry, Matthew Swenson Microscopy & Microanalysis 22 2016-02-01 http://journals.cambridge.org/fulltext_content/supplementary/MAM22_S3_minisite/7337/0690.pdf |
| Publication | The effects of oxide evolution on mechanical properties in proton- and neutron-irradiated Fe-9%Cr ODS steel Matthew Swenson, Corey Dolph, Janelle Wharry Journal of Nuclear Materials 479 2016-10-01 https://www.sciencedirect.com/science/article/pii/S0022311516303889#! |
| Publication | The comparison of microstructure and nanocluster evolution in proton and neutron irradiated Fe?9%Cr ODS steel to 3 dpa at 500 °C Janelle Wharry, Matthew Swenson Journal of Nuclear Materials 467 2015-12-01 https://doi.org/10.1016/j.jnucmat.2015.09.022 |
| RTE Number | 486 |