Abstract
Dual ion irradiations using 5 MeV defocused Fe2+ ions and co-injected He2+ ions were conducted on a ferritic-martensitic steel alloy, T91, in the temperature range of 406 °C–570 °C over a damage range of 14.6–35 dpa followed by characterization of the microstructure using transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM). Dislocation loops were observed to increase in diameter and decrease in density with temperature until only network dislocations were observed at the highest temperatures of 520 °C and 570 °C. Swelling exhibited the expected bell-shaped trend with temperature following the number density of cavities, peaking at 460 °C and with a bimodal size distribution except at 520 °C and 570 °C. Nickel- and silicon-rich clusters formed under dual ion irradiations near the surface at all but the highest temperatures of 520 °C and 570 °C. Very little Cr and Si segregation was observed at lath boundaries while Ni enriched at all temperatures examined. Segregation of Cr and Ni appeared to saturate by 17 dpa, while Si enriched up to 35 dpa. The dislocation and cavity microstructures of dual ion irradiated T91 and T91 irradiated in the BOR-60 fast reactor matched extremely well using a temperature shift of +60–70 °C. However, segregation to grain boundaries and formation of nickel-silicon rich clusters were minimal in the dual ion irradiated T91 and less than that in T91 irradiated in the BOR-60 fast reactor.
| Original language | English |
|---|---|
| Article number | 151831 |
| Journal | Journal of Nuclear Materials |
| Volume | 527 |
| DOIs | |
| State | Published - Dec 15 2019 |
| Externally published | Yes |
Funding
Primary support for this research was provided by Department of Energy under contract DE-NE0000639. Support for S. Taller partially provided by a DOE NEUP Graduate Fellowship. The authors gratefully acknowledge Ovidiu Toader, Fabian Naab, Thomas Kubley at the Michigan Ion Beam Laboratory and Ethan Uberseder for their assistance with the dual ion irradiations. The authors would also like to acknowledge NSF grant #DMR-9871177 for support of the JEOL 2010F TEM and NSF grant #DMR-0320740 for support of the JEOL 2100F S/TEM at the Michigan Center for Materials Characterization. This research was performed, in part, using instrumentation (FEI Talos) provided by the Department of Energy, Office of Nuclear Energy, Nuclear Technology R&D (formerly Fuel Cycle R&D) Program, and the Nuclear Science User Facilities through the DOE in the United States. Primary support for this research was provided by Department of Energy under contract DE-NE0000639 . Support for S. Taller partially provided by a DOE NEUP Graduate Fellowship . The authors gratefully acknowledge Ovidiu Toader, Fabian Naab, Thomas Kubley at the Michigan Ion Beam Laboratory and Ethan Uberseder for their assistance with the dual ion irradiations. The authors would also like to acknowledge NSF grant # DMR-9871177 for support of the JEOL 2010F TEM and NSF grant # DMR-0320740 for support of the JEOL 2100F S/TEM at the Michigan Center for Materials Characterization. This research was performed, in part, using instrumentation (FEI Talos) provided by the Department of Energy, Office of Nuclear Energy, Nuclear Technology R&D (formerly Fuel Cycle R&D) Program, and the Nuclear Science User Facilities through the DOE in the United States.
Keywords
- Emulation
- Ferritic-martensitic steel
- Ion irradiation
- Microstructure
- Swelling