NSUF 15-539: Post-irradiation Examinations on a Ferritic ODS Steel Irradiated at 450C
Technical Abstract Please describe the project objectives including methods to be employed, and the potential impact to the state-of-the-knowledge if the research is successful. The abstract must also indicate the expected period of performance. The addition of oxide powders such as yttria and alumina during mechanical alloying introduces dense dispersive oxygen-enriched nanoparticles into steel matrices. These nanoparticles can not only significantly enhance the mechanical strength and creep resistance, but also provide extra interfaces, which can behave as sinks of defects under irradiation. Therefore, ODS steels are regarded as promising candidates of the structural materials in advanced nuclear systems, which require excellent mechanical properties and robust radiation tolerance at high temperatures. Previous studies on neutron and ion irradiated MA957 indicate that that dislocation network forms and that the oxygen-enriched nanoparticles remain stable in the high dose regime. However, very limited research has been done for the radiation induced microstructural modifications in neutron-irradiated ODS steels in low dose regime. Meanwhile, it is also valuable to compare these alterations in microstructures in MA957 with those in model alloys and non-ODS commercial alloys. All the knowledge helps understand the radiation resistance mechanisms of ODS steels and provides insight into the development of prospective ODS or nanostructured advanced alloys. To realize these objectives, three MA957 specimens irradiated in ATR at 450C with three dose conditions (0.01dpa, 0.1dpa and 1dpa) are proposed to be investigated by a series of advanced characterization techniques including atom probe tomography (APT) and transmission electron microscopy (TEM). 450C irradiation temperature was chosen since high-temperature performance is crucial for ODS alloys. Also, previous PIE results of Fe-Cr base alloys indicate that the responses of the materials are quite different between 300C and 450C irradiation temperatures. As the PIE of the MA957 samples irradiated at 300C with the same dose condition will be supported by another project, it is relevant to investigate the 450C neutron-irradiated MA957 specimens. Focused ion beam (FIB) will be utilized to prepare tip specimens for successive atom probe experiments since it does not involve any preferential corrosion as electropolishing does. APT will be used to retrieve the 3D element distribution in the samples. Then we will measure the variations in chemical composition and size distribution of the small-scale oxygen-enriched nanoparticles (5nm). Thus, a comprehensive understanding of radiation-induced microstructural modifications in MA957 at 450C and within the low-dose regime will be established due to the accomplishment of this proposed PIE project. FIB preparation will take 3 days; TEM investigation will take 4 days; APT investigation will take another 3 days. The total time is within the RTE proposal limitation.
Papildoma informacija
| Laukas | Reikšmė |
|---|---|
| Awarded Institution | University of Illinois |
| Embargo End Date | 2026-02-27 |
| Facility Tech Lead | Jeff Terry, Mukesh Bachhav |
| NSUF Call | FY 2015 RTE 1st Call |
| PI | James Stubbins |
| Project Member | Dr. Yinbin Miao, Principal Materials Scientist - Argonne National Laboratory (https://orcid.org/0000-0002-3128-4275) |
| Project Member | Dr. Xiang Liu, Postdoctoral Research Associate - Idaho National Laboratory (https://orcid.org/0000-0002-2634-1888) |
| Project Type | RTE |
| Publication | Stability of nanoclusters in an oxide dispersion strengthened alloy under neutron irradiation Xiang Liu, Yinbin Miao, Yaqiao Wu, Stuart Maloy, James Stubbins Scripta Materialia 138 2017-09-30 https://www.sciencedirect.com/science/article/pii/S1359646217302671#ac0005 |
| Publication | The comparison of microstructures and mechanical properties between 14 cr-Al and 14Cr-Ti ferritic ODS alloys Yinbin Miao, Kun Mo, James Stubbins, Xiang Liu Materials & Design 98 2016-05-15 http://www.sciencedirect.com/science/article/pii/S0264127516302611 |
| Publication | Ion-irradiation-induced microstructural modifications in ferritic/martensitic steel T91 Xiang Liu, Yinbin Miao, Meimei Li, Stuart Maloy, James Stubbins Journal of Nuclear Materials 490 2017-04-27 https://www.sciencedirect.com/science/article/pii/S0022311516304640#ack0010 |
| RTE Number | 539 |