Alumina grain growth and grain boundary segregation of FeCrAl-based oxide dispersion-strengthened alloys at high temperature

Abstract

FeCrAl-based oxide dispersion-strengthened alloys are currently being considered for accident-tolerant fuel cladding applications. In this study, the microstructure of alumina scales that formed on the alloys after oxidation at 1100 °C and 1200 °C, in an atmosphere containing water vapor, was investigated. The alumina grain growth and grain boundary segregation were analyzed using multiscale techniques such as oxidation kinetics, scanning electron microscopy, electron probe microanalysis, transmission electron microscopy, and backscattered electron diffraction, thus evaluating the diffusion of the reactive elements and alumina grain structure at different scales. A mechanism supporting the development of the alumina grain structure was proposed.