Convolution and spallation of oxides formed on Fe–Al alloys after short oxidation times

Abstract

A study of the oxidation of Fe–5Al alloys with additions of silicon and yttrium has shown that high stresses can develop within the oxide scale. These stresses occur after very short oxidation times (<5 min at 1000 °C)for samples that do not contain yttrium, but are not present in the scalesformed on alloys containing yttrium. A stress gradient develops across the scale with the oxide at the metal/oxide interface under the greatest compressive stress. Transmission electron microscopy and analysis were used to study cross-sections through the metal/oxide interfaces. It was found that a stress gradient was not present after oxidation at lower temperatures or when yttrium was present.MST/860