In situ oxidation analysis on Co-Al-W-Ti-Ta single-crystal alloy in an environmental TEM

Abstract Oxidation is a key drawback in the high temperature performance of superalloys, and it is scientifically and technologically important to determine its atomic scale oxidation. In this study, the oxidation mechanism of a γ/γ′ structured Co80Al7W8Ti4Ta1 single crystal superalloy was studied in situ down to the nano and atomic scales by directly inspecting the oxidation process in an environmental transmission electron microscope. The oxidation priority follows the order γ phase > γ/γ′ boundary > γ′ phase, indicating selective phase oxidation. In situ selective phase and elemental oxidation behaviours provide insight for the design of oxidation resistive superalloys.