Ultra-strong and strain-hardenable ultrafine-grained medium-entropy alloy via enhanced grain-boundary strengthening

Jeong Min Park, Dae Cheol Yang, Han Jin Kim, Dong Geun Kim, Sunghak Lee, Hyoung Seop Kim, Seok Su Sohn

Research output: Contribution to journalArticlepeer-review

31 Citations (Scopus)


An equiatomic VCoNi medium-entropy alloy possesses high sensitivity to grain-boundary strengthening, achieved by severe lattice distortions. Its ultrafine-grain structure enables 1.5 Gigapascal yield strength even for the fully recrystallized alloy with a single face-centered cubic structure. The high density of grain boundaries also generates high back stresses via piling up of massive dislocations, and the low cross-slip probabilities produce not only robust dislocation-mediated plasticity but also high back stress contribution to flow stress, which affords high strain-hardening capability to ultrafine-grain alloys, with 1.7 Gigapascal ultimate tensile strength with remarkable ductility. Our approach provides a new method for developing ultrastrong metallic materials.

Original languageEnglish
Pages (from-to)315-321
Number of pages7
JournalMaterials Research Letters
Issue number7
Publication statusPublished - 2021

Bibliographical note

Funding Information:
This work was supported by the National Research Foundation of Korea (grant number?NRF-2020R1C1C1003554); the Creative Materials Discovery Program of the NRF?funded by the Ministry of Science and ICT [grant number NRF-2016M3D1A1023384]; the Korea Institute for Advancement of Technology (KIAT) grant funded by the Korean Government (MOTIE) [grant number P0002019, The Competency Development Program for Industry Specialist]. J.M. Park is also supported by the Basic Science Research Program ?Fostering the Next Generation of Researchers? through the NRF funded by the Ministry of Education [grant number 2020R1A6A3A13073260].

Publisher Copyright:
© 2021 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.


  • Medium-entropy alloy
  • grain boundary strengthening
  • severe lattice distortion
  • severe plastic deformation
  • ultrafine grain structure

ASJC Scopus subject areas

  • General Materials Science


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