Hydrogen modified interface interaction of solution-annealed and cold-work stainless steel 316L in oxygenated high-temperature water

Abstract

ABSTRACT Composition and structure of the oxide films developed on stainless steels (SS) SA316L and CW316L with and without hydrogen charging were characterized after immersion in oxygenated high-temperature water. Results show that the oxide films grown upon all specimens consist of a double-layer structure. Hydrogen increases size of the outer oxide and modulates the oxide phase to favour the formation of spinel-type oxide. Charged hydrogen increases dislocation density and slip bands beneath the oxide-matrix interface and contributes to penetration oxidation occurring in SA316L sample. The formation of small-scale cracks on SA316L surfaces was facilitated by charged hydrogen, which is attributed to combined effects of hydrogen embrittlement at grain boundaries and hydrogen-induced hardening. Such a coupling effect of hydrogen and pre-deformation significantly enhanced the oxidation kinetics of SS 316L in oxygen-containing high-temperature water. Underlying mechanism of hydrogen effect on the interface potential drop and oxide growth kinetics was discussed.