Oxidation Behavior and Outward Diffusion of Al Along Oxide Grain Boundaries of FeCrAl Alloys Overdoped with Zr and Hf
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Date
2024-02-01
Authors
Daradkeh, Samer Issa Abdel Razzaq
Recalde, Oscar
Mousa, Marwan Suleiman
Sobola, Dinara
Boll, Torben
ORCID
0000-0002-0008-5265Advisor
Referee
Mark
Journal Title
Journal ISSN
Volume Title
Publisher
SPRINGER
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Abstract
The formation of the alpha-Al2O3 scale on reactive element (RE)-doped FeCrAl alloys is commonly believed to be primarily caused by inward oxygen transport along grain boundaries. However, this study suggests that metal ion outward diffusion also plays a role in the development of the oxide scales and their microstructural characteristics. The study examines the oxidation behavior and grain boundary outward diffusion of iron-chromium alloys containing similar to 10 at% aluminum and similar to 22 at% chromium, doped with an over-critical concentration of REs, i.e., Zr and Hf. All samples were investigated after thermal exposure at 1100 degrees C by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and atom probe tomography (APT). As a result of the overdoping, a considerable increase in oxide growth, an increase in the depth of internal oxidation, and RE-oxide formation near and at oxide grain boundaries (GBs) were observed as a consequence of increased inward and outward diffusion. The effect of overdoping manifests itself differently depending on the RE type and amount due to different solubility, ionic size, and electronic structure of alumina. The sample with Zr retained the adhesion of alumina to the alloy after the first and second thermal exposure, while Hf overdoping resulted in severe spallation after the second thermal exposure.
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Citation
HIGH TEMPERATURE CORROSION OF MATERIALS
. 2024, vol. 101, issue 1, p. 41-59.
https://link.springer.com/article/10.1007/s11085-023-10204-z
https://link.springer.com/article/10.1007/s11085-023-10204-z
Document type
Peer-reviewed
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Published version
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en