Microstructure, texture, and strength development during high-pressure torsion of crmnfeconi high-entropy alloy

Werner Skrotzki, Aurimas Pukenas, Eva Odor, Bertalan Joni, Tamas Ungar, Bernhard Völker, Anton Hohenwarter, Reinhard Pippan, Easo P. George

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

The equiatomic face-centered cubic high-entropy alloy CrMnFeCoNi was severely deformed at room and liquid nitrogen temperature by high-pressure torsion up to shear strains of about 170. Itsmicrostructurewas analyzed by X-ray line profile analysis and transmission electronmicroscopy and its texture by X-ray microdiffraction. Microhardness measurements, after severe plastic deformation, were done at room temperature. It is shown that at a shear strain of about 20, a steady state grain size of 24 nm, and a dislocation density of the order of 1016 m-2 is reached. The dislocations are mainly screw-type with low dipole character. Mechanical twinning at room temperature is replaced by a martensitic phase transformation at 77 K. The texture developed at room temperature is typical for sheared face-centered cubic nanocrystalline metals, but it is extremely weak and becomes almost random after high-pressure torsion at 77 K. The strength of the nanocrystalline material produced by high-pressure torsion at 77 K is lower than that produced at room temperature. The results are discussed in terms of different mechanisms of deformation, including dislocation generation and propagation, twinning, grain boundary sliding, and phase transformation.

Original languageEnglish
Article number336
JournalCrystals
Volume10
Issue number4
DOIs
Publication statusPublished - Apr 2020

Keywords

  • High-entropy alloy
  • High-pressure torsion
  • Microstructure
  • Phase transformation
  • Strength
  • Texture

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Inorganic Chemistry

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    Skrotzki, W., Pukenas, A., Odor, E., Joni, B., Ungar, T., Völker, B., Hohenwarter, A., Pippan, R., & George, E. P. (2020). Microstructure, texture, and strength development during high-pressure torsion of crmnfeconi high-entropy alloy. Crystals, 10(4), [336]. https://doi.org/10.3390/cryst10040336