In-situ TEM study of microstructural evolution in NFA and Cr3C2@SiC-NFA composite during ion irradiation

Bawane, Kaustubh; Lu, Kathy; Bai, Xian-Ming; Chen, Wei-Ying; Li, Meimei

doi:10.1016/j.mtla.2019.100412

Title: In-situ TEM study of microstructural evolution in NFA and Cr₃C₂@SiC-NFA composite during ion irradiation

Journal Article · Fri Jul 26 00:00:00 EDT 2019 · Materialia

DOI:https://doi.org/10.1016/j.mtla.2019.100412· OSTI ID:1546959

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^[1]; Bai, Xian-Ming ^[1]; Chen, Wei-Ying ^[2]; Li, Meimei ^[2]

Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States)
Argonne National Laboratory (ANL), Lemont, IL (United States)

In this article, the ion irradiation responses of a Fe-based nanostructured ferritic alloy or ‘NFA’ (Fe–9Cr–2W–0.2V–0.4Ti–0.3Y₂O₃) and a Cr₃C₂@SiC-NFA composite were assessed. In-situ ion irradiation with TEM observation was carried out by using 1 MeV Kr⁺⁺ ions at doses of 0, 1, 3, 5, 10 dpa and temperatures of 300 °C and 450 °C. Both the NFA and Cr₃C₂@SiC-NFA samples showed significant dislocation density after 10 dpa at 300 °C. However, the Cr₃C₂@SiC-NFA composite showed a significantly lower dislocation loop density and a smaller average loop size during the irradiation at 450 °C as opposed to the NFA. At 300 °C, 1/2<111> type dislocation loops were observed in both the NFA and Cr₃C₂@SiC-NFA samples. Interestingly, at 450 °C, <100> type loops were dominant in the NFA sample while 1/2<111> type loops were still dominant in the Cr₃C₂@SiC-NFA sample. The results were discussed based on the large surface sink effects and enhanced interstitial-vacancy recombination at higher temperatures. Lastly, the additional Si element in the Cr₃C₂@SiC-NFA sample might have played a significant role in determining the dominant loop types.