Beyond Solid Solution High-Entropy Alloys

Beyond Solid Solution High-Entropy Alloys: Tailoring Magnetic Properties via Spinodal Decomposition

Rao, Ziyuan (Max-Planck-Institut für Eisenforschung)
Dutta, B. (TU Delft (OLD) MSE-7)
Körmann, F.H.W. (TU Delft (OLD) MSE-7; Max-Planck-Institut für Eisenforschung)
Lu, Wenjun (Max-Planck-Institut für Eisenforschung; Southern University of Science and Technology of China)
Zhou, Xuyang (Max-Planck-Institut für Eisenforschung)
Liu, Chang (Max-Planck-Institut für Eisenforschung)
da Silva, Alisson Kwiatkowski (Max-Planck-Institut für Eisenforschung)
Wiedwald, Ulf (Universität Duisburg-Essen)
Spasova, Marina (Universität Duisburg-Essen)
Farle, Michael (Universität Duisburg-Essen)
Ponge, Dirk (Max-Planck-Institut für Eisenforschung)
Gault, Baptiste (Max-Planck-Institut für Eisenforschung; Imperial College London)
Neugebauer, Jörg (Max-Planck-Institut für Eisenforschung)
Raabe, Dierk (Max-Planck-Institut für Eisenforschung)
Li, Zhiming (Max-Planck-Institut für Eisenforschung; Central South University China)

2021

Since its first emergence in 2004, the high-entropy alloy (HEA) concept has aimed at stabilizing single- or dual-phase multi-element solid solutions through high mixing entropy. Here, this strategy is changed and renders such massive solid solutions metastable, to trigger spinodal decomposition for improving the alloys’ magnetic properties. The motivation for starting from a HEA for this approach is to provide the chemical degrees of freedom required to tailor spinodal behavior using multiple components. The key idea is to form Fe-Co enriched regions which have an expanded volume (relative to unconstrained Fe-Co), due to coherency constraints imposed by the surrounding HEA matrix. As demonstrated by theory and experiments, this leads to improved magnetic properties of the decomposed alloy relative to the original solid solution matrix. In a prototype magnetic FeCoNiMnCu HEA, it is shown that the modulated structures, achieved by spinodal decomposition, lead to an increase of the Curie temperature by 48% and a simultaneous increase of magnetization by 70% at ambient temperature as compared to the homogenized single-phase reference alloy. The findings thus open a pathway for the development of advanced functional HEAs.

coherency constraints
density functional theory
high-entropy alloys
magnetic properties
spinodal decomposition

http://resolver.tudelft.nl/uuid:a88a4d6b-b170-437e-be1a-e7d52f76b26c

https://doi.org/10.1002/adfm.202007668

1616-301X

Advanced Functional Materials, 31 (7)

Institutional Repository

journal article

© 2021 Ziyuan Rao, B. Dutta, F.H.W. Körmann, Wenjun Lu, Xuyang Zhou, Chang Liu, Alisson Kwiatkowski da Silva, Ulf Wiedwald, Marina Spasova, Michael Farle, Dirk Ponge, Baptiste Gault, Jörg Neugebauer, Dierk Raabe, Zhiming Li