Ultrastrong Medium-Entropy Single-Phase Alloys Designed via Severe Lattice Distortion

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

Research output: Contribution to journalArticle

34 Citations (Scopus)

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
JournalAdvanced Materials
Volume31
Issue number8
DOIs
Publication statusPublished - 2019 Feb 22
Externally publishedYes

Keywords

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

ASJC Scopus subject areas

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering

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    Sohn, S. S., Kwiatkowski da Silva, A., Ikeda, Y., Körmann, F., Lu, W., Choi, W. S., Gault, B., Ponge, D., Neugebauer, J., & Raabe, D. (2019). Ultrastrong Medium-Entropy Single-Phase Alloys Designed via Severe Lattice Distortion. Advanced Materials, 31(8), [1807142]. https://doi.org/10.1002/adma.201807142