Irradiation accelerated corrosion of alumina-forming austenitic steels in supercritical CO2: The oxide scale formed within an individual grain or affected by grain boundary.

The irradiation accelerated corrosion within monolayer grains of a new AFA steel exposed to sCO 2 are studied. The presence of irradiation induced dislocation loops accelerate element diffusion and reduces corrosion resistance by ∼44%. Many oxide scale features are firstly found, including a two-phase inner layer consisting of Ni-rich austenite and Cr-rich spinel, and Al 2 O 3 /SiO 2 oxide precipitates. Irradiation leads to an additional Cr-rich oxide layer at the bottom of inner layer and a narrower Al 2 O 3 band in the internal oxidation layer. Irradiation also induces Cr depletion at grain boundaries, thereby impeding the formation of a protective Cr-rich oxide scale. • Coupling effects of irradiation and corrosion of a new AFA steel exposed to sCO 2 are firstly studied. • Irradiation induced dislocation loops accelerate the element diffusion, while it is not enough to form a protective Cr 2 O 3 /Al 2 O 3 in sCO 2. • A two-phase inner layer (Ni-rich austenite + Cr-rich spinel), and Al 2 O 3 /SiO 2 oxide precipitates are formed in sCO 2. • Irradiation results in an extra Cr-rich oxide layer and a narrower Al 2 O 3 band near the O/M interface. • Irradiation induces Cr depletion at grain boundaries, then the protective Cr-rich oxide scale cannot be easily formed here. [ABSTRACT FROM AUTHOR]