Superior high-temperature oxidation resistance of nanocrystalline 304 austenitic stainless steel containing a small amount of Si

Improving the high-temperature oxidation resistance of steels by excessive Si addition to form a continuous silica healing layer would deteriorate the mechanical, welding and irradiation properties. Here, we report a thermally stable nanocrystalline 304 (NC-304) austenitic stainless steel with a low...

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Veröffentlicht in:Scripta materialia 2021-11, Vol.204, p.114155, Article 114155
Hauptverfasser: Cai, X.C., Ding, S.J., Jin, S.B., Xu, L.D., Liu, G.Y., Sun, B.R., Shen, T.D.
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Sprache:eng
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Zusammenfassung:Improving the high-temperature oxidation resistance of steels by excessive Si addition to form a continuous silica healing layer would deteriorate the mechanical, welding and irradiation properties. Here, we report a thermally stable nanocrystalline 304 (NC-304) austenitic stainless steel with a low Si content (less than 1 wt.%) and superior high-temperature oxidation resistance. The segregated Si at the grain boundaries (GBs) of NC-304 presets a nanoscale Si-enriched network for the formation of a continuous SiO2 GB network during the high-temperature oxidation. Besides, the high-density La-Si-O-rich nanoprecipitates can serve as heterogeneous formation sites for SiO2, promoting the formation of a continuous SiO2 phase along the GB network. The unique nanocrystalline microstructure and element distribution feature of Si in NC-304 accelerate the construction of a continuous SiO2 healing layer, which effectively eliminates the breakaway oxidation found in coarse-grained 304 counterpart and significantly reduces the high-temperature oxidation rate at least to 1000 °C. [Display omitted]
ISSN:1359-6462
1872-8456
DOI:10.1016/j.scriptamat.2021.114155