Abstract
Oxide-dispersion-strengthened steels are the most promising structural materials for next-generation nuclear energy systems because of their excellent resistance to both irradiation damage and high-temperature creep1,2,3,4. Although it has been known for a decade that the extraordinary mechanical properties of oxide-dispersion-strengthened steels originate from highly stabilized oxide nanoclusters with a size smaller than 5 nm, the structure of these nanoclusters has not been clarified and remains as one of the most important scientific issues in nuclear materials research2,3,4,5,6,7. Here we report the atomic-scale characterization of the oxide nanoclusters using state-of-the-art Cs-corrected transmission electron microscopy. This study provides compelling evidence that the nanoclusters have a defective NaCl structure with a high lattice coherency with the bcc steel matrix. Plenty of point defects as well as strong structural affinity of nanoclusters with the steel matrix seem to be the most important reasons for the unusual stability of the clusters at high temperatures and in intensive neutron irradiation fields.
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Change history
27 October 2011
In the version of this Letter originally published, the bar over the number 1 is missing in two instances. This error has been corrected only in the HTML version of the Letter. The PDF has no change.
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Acknowledgements
This work was sponsored by ‘Global COE for Materials Research and Education’, ‘World Premier International (WPI) Research Center Initiative for Atoms, Molecules and Materials’, MEXT, Japan. We thank Okunishi of JEOL for his technical assistance and D. T. Hoelzer at ORNL, USA for providing 14YWT samples for this study.
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M.W.C. and C.T.L. planned this project. A.H. and M.W.C. designed research, analysed data, constructed models and wrote the paper. A.H. contributed to STEM experiments and image simulation. T.F. contributed to EELS analysis. Y.R.W. contributed to TEM specimen preparation. J.H.S. and C.T.L. contributed to sample preparation. All authors discussed the results and commented on the manuscript.
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Hirata, A., Fujita, T., Wen, Y. et al. Atomic structure of nanoclusters in oxide-dispersion-strengthened steels. Nature Mater 10, 922–926 (2011). https://doi.org/10.1038/nmat3150
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DOI: https://doi.org/10.1038/nmat3150