Deformation behavior of nanocrystalline and ultrafine-grained CoCrCuFeNi high-entropy alloys

Seungjin Nam, Jun Yeon Hwang, Jonggyu Jeon, Jihye Park, DongHyun Bae, Moon J. Kim, Jae Hun Kim, Hyunjoo Choi

Research output: Contribution to journalArticle

Abstract

Nanocrystalline (NC) and ultrafine-grained (UFG) CoCrCuFeNi high-entropy alloy (HEA) with grain size ranging between 59 and 386 nm was produced via powder metallurgy and heat treatment. The as-sintered HEA exhibited two face-centered cubic (FCC) phases (CoCrFeNi-rich and Cu-rich phases) and a small grain size (59 nm), whereas the alloy after heat treatment at 1000 °C exhibited a CoCuFeNi-rich phase with FCC structure and relatively larger grain size (386 nm). Moreover, the yield strength decreased from 1930 to 883 MPa, and plastic strain to failure increased by 8-32%. In terms of microstructural evolution, grain boundary strengthening coupled with lattice distortion was the dominant strengthening mechanism for NC HEAs. Furthermore, the coefficient for boundary strengthening was higher in the HEAs than in the corresponding pure elemental metals with FCC structure, possibly because of significant lattice distortion. The UFG HEAs exhibited high strength and good ductility because of the activation of dislocation.

Original languageEnglish
JournalJournal of Materials Research
DOIs
Publication statusAccepted/In press - 2019 Jan 1

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Entropy
grain size
entropy
heat treatment
Heat treatment
powder metallurgy
Microstructural evolution
Powder metallurgy
yield strength
high strength
ductility
Crystal lattices
Yield stress
Ductility
Plastic deformation
Grain boundaries
plastics
grain boundaries
Metals
Chemical activation

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

Cite this

Nam, Seungjin ; Hwang, Jun Yeon ; Jeon, Jonggyu ; Park, Jihye ; Bae, DongHyun ; Kim, Moon J. ; Kim, Jae Hun ; Choi, Hyunjoo. / Deformation behavior of nanocrystalline and ultrafine-grained CoCrCuFeNi high-entropy alloys. In: Journal of Materials Research. 2019.
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abstract = "Nanocrystalline (NC) and ultrafine-grained (UFG) CoCrCuFeNi high-entropy alloy (HEA) with grain size ranging between 59 and 386 nm was produced via powder metallurgy and heat treatment. The as-sintered HEA exhibited two face-centered cubic (FCC) phases (CoCrFeNi-rich and Cu-rich phases) and a small grain size (59 nm), whereas the alloy after heat treatment at 1000 °C exhibited a CoCuFeNi-rich phase with FCC structure and relatively larger grain size (386 nm). Moreover, the yield strength decreased from 1930 to 883 MPa, and plastic strain to failure increased by 8-32{\%}. In terms of microstructural evolution, grain boundary strengthening coupled with lattice distortion was the dominant strengthening mechanism for NC HEAs. Furthermore, the coefficient for boundary strengthening was higher in the HEAs than in the corresponding pure elemental metals with FCC structure, possibly because of significant lattice distortion. The UFG HEAs exhibited high strength and good ductility because of the activation of dislocation.",
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year = "2019",
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Deformation behavior of nanocrystalline and ultrafine-grained CoCrCuFeNi high-entropy alloys. / Nam, Seungjin; Hwang, Jun Yeon; Jeon, Jonggyu; Park, Jihye; Bae, DongHyun; Kim, Moon J.; Kim, Jae Hun; Choi, Hyunjoo.

In: Journal of Materials Research, 01.01.2019.

Research output: Contribution to journalArticle

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AU - Hwang, Jun Yeon

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AU - Bae, DongHyun

AU - Kim, Moon J.

AU - Kim, Jae Hun

AU - Choi, Hyunjoo

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