TY - JOUR
T1 - Accelerated oxidation in ductile refractory high-entropy alloys
AU - Sheikh, Saad
AU - Bijaksana, Muhammad Kurnia
AU - Motallebzadeh, Amir
AU - Shafeie, Samrand
AU - Lozinko, Adrianna
AU - Gan, Lu
AU - Tsao, Te Kang
AU - Klement, Uta
AU - Canadinc, Demircan
AU - Murakami, Hideyuki
AU - Guo, Sheng
N1 - Funding Information:
SS and SG are grateful for the financial support from Areas of Advance Materials Science from Chalmers University of Technology .
Publisher Copyright:
© 2018
PY - 2018/6
Y1 - 2018/6
N2 - 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 °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.
AB - 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 °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.
KW - High temperature materials
KW - Oxidation resistance
KW - Pesting
KW - Refractory high-entropy alloys
UR - http://www.scopus.com/inward/record.url?scp=85048588474&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85048588474&partnerID=8YFLogxK
U2 - 10.1016/j.intermet.2018.04.001
DO - 10.1016/j.intermet.2018.04.001
M3 - Article
AN - SCOPUS:85048588474
SN - 0966-9795
VL - 97
SP - 58
EP - 66
JO - Intermetallics
JF - Intermetallics
ER -