Publication: Accelerated oxidation in ductile refractory high-entropy alloys
Program
KU-Authors
KU Authors
Co-Authors
Sheikh, Saad
Bijaksana, Muhammad Kurnia
Shafeie, Samrand
Lozinko, Adrianna
Gan, Lu
Tsao, Te-Kang
Klement, Uta
Murakami, Hideyuki
Guo, Sheng
Publication Date
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Type
Embargo Status
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Abstract
Refractory high-entropy alloys (RHEAs) are promising candidates for new-generation high temperature materials, but they generally suffer from room temperature brittleness and unsatisfactory high-temperature oxidation resistance. There currently lack efforts to address to these two critical issues for RHEAs at the same time. In this work, the high temperature oxidation resistance of a previously identified ductile Hf0.5Nb0.5Ta0.5Ti1.5Zr RHEA is studied. An accelerated oxidation or more specifically, pesting, in the temperature range of 600-1000 degrees C is observed for the target RHEA, where the oxidation leads the material to catastrophically disintegrate into powders. The pesting mechanism is studied here, and is attributed to the failure in forming protective oxide scales accompanied by the accelerated internal oxidation. The simultaneous removal of zirconium and hafnium can eliminate the pesting phenomenon in the alloy. It is believed that pesting can also occur to other equiatomic and non-equiatomic quinary Hf-Nb-Ta-Ti-Zr or quaternary Hf-Nb-Ti-Zr and Hf-Ta-Ti-Zr RHEAs, where all currently available ductile RHEAs are identified. Therefore, the results from this work will provide crucial perspectives to the further development of RHEAs as novel high-temperature materials, with balanced room-temperature ductility and high-temperature oxidation resistance.
Source
Publisher
Elsevier
Subject
Chemistry, Physical chemistry, Materials Science, Metallurgy, Metallurgical engineering
Citation
Has Part
Source
Intermetallics
Book Series Title
Edition
DOI
10.1016/j.intermet.2018.04.001