Ultrastrong medium-entropy single-phase alloys designed via severe lattice distortion

Ultrastrong medium-entropy single-phase alloys designed via severe lattice distortion

Sohn, Seok Su (Max-Planck-Institut für Eisenforschung)
Kwiatkowski da Silva, Alisson (Max-Planck-Institut für Eisenforschung)
Ikeda, Yuji (Max-Planck-Institut für Eisenforschung; Kyoto University)
Körmann, F.H.W. (TU Delft (OLD) MSE-7; Max-Planck-Institut für Eisenforschung)
Lu, Wenjun (Max-Planck-Institut für Eisenforschung)
Choi, Won Seok (Korea Advanced Institute of Science and Technology)
Gault, Baptiste (Max-Planck-Institut für Eisenforschung)
Ponge, Dirk (Max-Planck-Institut für Eisenforschung)
Neugebauer, Jörg (Max-Planck-Institut für Eisenforschung)
Raabe, Dierk (Max-Planck-Institut für Eisenforschung)

2019

Severe lattice distortion is a core effect in the design of multiprincipal element alloys with the aim to enhance yield strength, a key indicator in structural engineering. Yet, the yield strength values of medium- and high-entropy alloys investigated so far do not substantially exceed those of conventional alloys owing to the insufficient utilization of lattice distortion. Here it is shown that a simple VCoNi equiatomic medium-entropy alloy exhibits a near 1 GPa yield strength and good ductility, outperforming conventional solid-solution alloys. It is demonstrated that a wide fluctuation of the atomic bond distances in such alloys, i.e., severe lattice distortion, improves both yield stress and its sensitivity to grain size. In addition, the dislocation-mediated plasticity effectively enhances the strength–ductility relationship by generating nanosized dislocation substructures due to massive pinning. The results demonstrate that severe lattice distortion is a key property for identifying extra-strong materials for structural engineering applications.

ab initio calculation
atomic bond distances
lattice distortion
medium-entropy alloys
tensile properties

http://resolver.tudelft.nl/uuid:f95f3963-1869-4ba9-9cd1-c0e1ec5ea9be

https://doi.org/10.1002/adma.201807142

2019-06-28

0935-9648

Advanced Materials, 31 (8)

Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.

Institutional Repository

journal article

© 2019 Seok Su Sohn, Alisson Kwiatkowski da Silva, Yuji Ikeda, F.H.W. Körmann, Wenjun Lu, Won Seok Choi, Baptiste Gault, Dirk Ponge, Jörg Neugebauer, Dierk Raabe