Oxidation-Induced Rhenium Evaporation in Ni-Based Single Crystal Superalloy Thin Lamella

Abstract Rhenium is the key element for improving the mechanical properties in γ/γ' structure single-crystal Ni-based superalloys, but its oxidation-induced evaporation results in a detrimental decrease in corrosion resistance. The in situ Re evaporation process of a single lamella of a high Re-containing Ni-based superalloy is recorded in an environmental transmission electron microscope. The local aggregation of Re in the inner border of the γ phase and subsequent evaporation forms channels for the accelerated oxidation of the base and other elements. The real oxidation process of Re evaporation provides detailed and essential information on corrosive gas resistance properties at the nanoscale.