Compatibility of Fe-Cr-Al and Fe-Cr-Al-Mo oxide dispersion strengthened steels with static liquid sodium at 700?

The corrosion behavior and tensile properties of oxide dispersion strengthened (ODS) FeCr, FeCrAl, Fe-CrAlMo steels and 316H stainless steel were evaluated after 10 0 0 h at 700 ? in static sodium with and without an oxygen getter (Zr foil). Without Zr foil to getter the dissolved oxygen in the liquid sodium, combined oxidation (formation of Cr, Fe-rich or Al-rich oxides) and dissolution of the studied materials was observed. For the ODS FeCr, Cr-and Fe-rich oxide formation and dissolution induced Cr depletion in the underlying alloy and led to the formation of laves phases that were observed to be detrimental to the room temperature tensile properties. For ODS FeCrAlMo and FeCrAl Al-rich oxide formation and dissolution resulted in Al depletion in the underlying alloys but did not impact tensile properties at room temperature. For 316H temperature induced sensitization combined with oxidation decreased room temperature tensile properties. With Zr foil added as oxygen getter, roughened surfaces and Al de-pletion profiles suggested the dissolution of ODS FeCr and FeCrAl into the liquid sodium while limited dissolution was observed for ODS FeCrAlMo and 316H. For the 316H and ODS FeCrAlMo steels, precipitates were formed at the grain boundaries after exposure. Tensile properties of ODS FeCr, FeCrAl and FeCrAlMo were not affected by the 10 0 0 h corrosion exposure with Zr foil added to the sodium but for 316H temperature-induced grain boundary sensitization negatively affected the tensile properties.(c) 2022 Elsevier B.V. All rights reserved.

Automated summary

In this study, the corrosion behavior and tensile properties of ODS steels and stainless steel after high temperature exposure were evaluated. Without an oxygen getter, the oxidation and dissolution of materials negatively affected the properties. With the addition of an oxygen getter, limited dissolution was observed and it did not impact the tensile properties.