Initial Oxidation of a Third-Generation Ni-Based Superalloy Analyzed by in situ Environmental TEM

Understanding an initial oxidation mechanism is important for superalloys since a small amount of oxidation can induce rapid follow-up that expands corrosion and can cause catastrophic failure of an aircraft. We reveal the mechanism of initial oxidation on a third-generation Ni-based superalloy by directly visualizing the nano- and atomic-scale dynamic evolution of initial oxidation on a Cs-corrected environmental transmission electron microscope at temperatures of up to 900 °C. The local aggregation of rhenium on the inner border of the γ phase prompts the initial oxidation, which then accelerates to full oxidation. The study provides a direct dynamic initial oxidation scene and shows the intrinsic oxidation mechanism in a way that traditional research cannot reach.