Accelerated oxidation in ductile refractory high-entropy alloys
Journal article, 2018
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.
Refractory high-entropy alloys
Pesting
High temperature materials
Oxidation resistance
Author
Saad Ahmed Sheikh
Chalmers, Industrial and Materials Science, Materials and manufacture
Muhammad Kurnia Bijaksana
Chalmers, Industrial and Materials Science
Amir Motallebzadeh
Koç University
Samrand Shafeie
Uppsala University
Adrianna Lozinko
Chalmers, Industrial and Materials Science, Materials and manufacture
Lu Gan
Waseda University
National Institute for Materials Science (NIMS)
Te-Kang Tsao
National Institute for Materials Science (NIMS)
Uta Klement
Chalmers, Industrial and Materials Science, Materials and manufacture
Demircan Canadinc
Koç University
Hideyuki Murakami
Waseda University
National Institute for Materials Science (NIMS)
Sheng Guo
Chalmers, Industrial and Materials Science, Materials and manufacture
Intermetallics
0966-9795 (ISSN)
Vol. 97 58-66Subject Categories
Ceramics
Metallurgy and Metallic Materials
Corrosion Engineering
DOI
10.1016/j.intermet.2018.04.001