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

Seok Su Sohn*, Alisson Kwiatkowski da Silva, Yuji Ikeda, Fritz Körmann, Wenjun Lu, Won Seok Choi, Baptiste Gault, Dirk Ponge, Jörg Neugebauer, Dierk Raabe

*Corresponding author for this work

    Research output: Contribution to journalArticleScientificpeer-review

    109 Citations (Scopus)
    65 Downloads (Pure)

    Abstract

    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.

    Original languageEnglish
    Article number1807142
    Number of pages8
    JournalAdvanced Materials
    Volume31
    Issue number8
    DOIs
    Publication statusPublished - 2019

    Bibliographical note

    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.

    Keywords

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

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