Helium effects on microstructural evolution in tempered martensitic steels: In situ helium implanter studies in HFIR
Microstructural evolutions in tempered martensitic steels (TMS) under neutron-irradiation, at fusion relevant He/dpa ratios and dpa rates, were characterized using a novel in situ He-implanter technique. F82H-mod3 was irradiated at 500 C in HFIR to a nominal 9 dpa and 190 or 380 appm He in both in the as-tempered (AT) and 20% cold-worked (CW) conditions. In all cases, a high number density of 1-2 nm He-bubbles were observed, along with fewer but larger 10 nm void-like faceted cavities. The He-bubbles form preferentially on dislocations and various interfaces. A slightly larger number of smaller He bubbles were observed in the CW condition. The lower He/dpa ratio produced slightly smaller and fewer He-bubbles. Comparisons of these observations to the results in nano-structured ferritic alloy (NFA) MA957 provide additional evidence that TMS may be susceptible to He-embrittlement as well as void swelling at fusion relevant He concentrations, while NFA are much more resistant to these degradation phenomena.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 963836
- Report Number(s):
- PNNL-SA-66972; JNUMAM; AT6020100; TRN: US200918%%241
- Journal Information:
- Journal of Nuclear Materials, 386:338-341, Vol. 386; ISSN 0022-3115
- Country of Publication:
- United States
- Language:
- English
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