Oxidation-induced rhenium evaporation in Ni-based single crystal superalloy thin lamella

Rhenium is the key element for improving the mechanical properties in gamma/gamma' structure single-crystal Nibased 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 gamma 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. (C) 2021 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Automated summary

Rhenium is crucial in enhancing the mechanical properties of gamma/gamma' structure single-crystal Ni-based superalloys, but its oxidation-induced evaporation can lead to a decrease in corrosion resistance. The in situ Re evaporation process in a high Re-containing Ni-based superalloy was observed, showing local aggregation in the gamma phase and subsequent formation of channels for accelerated oxidation. This real-time oxidation process of Re evaporation offers detailed nanoscale information on corrosive gas resistance properties.