Reversible dislocation movement, martensitic transformation and nano-twinning during elastic cyclic loading of a metastable high entropy alloy

S. M. Vakili, A. Zarei-Hanzaki, A. S. Anoushe, H. R. Abedi, M. H. Mohammad-Ebrahimi, M. Jaskari, Seok Su Sohn, D. Ponge, L. P. Karjalainen

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2 Citations (Scopus)

Abstract

The present study contends with the room temperature microstructural response of a non-equiatomic metastable high entropy alloy to the elastic cyclic deformation. The stress and strain-induced martensite formation and reversion are recognized as the main microstructural evolutions which are directly correlated with the reversibility of dislocation movement. Two different patterns of reversion for deformation driven epsilon martensite are identified. Full reversion of stress-induced epsilon martensite results in development of nano-twined matrix, the various aspects of which have been described through a dislocation-based model. The strain-induced martensite also goes through partial reversion leading to lath fragmentation which in-turn significantly influences the martensite stability. Interestingly, the presence of a well-developed dislocation substructure is characterized within the martensite bands, which seems to be phenomenal owing to the low imposed strain, low temperature and low stacking fault energy of the experimented material. The development of vein and wall/channel structures is justified through proposing a conceptual based model regarding the interaction of the stacking faults and subsequent generation of the perfect dislocations.

Original languageEnglish
Pages (from-to)474-492
Number of pages19
JournalActa Materialia
Volume185
DOIs
Publication statusPublished - 2020 Feb 15

Keywords

  • Dislocation structures
  • Elastic cyclic deformation
  • High entropy alloys
  • Martensitic transformation
  • Reversible dislocation movement

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Polymers and Plastics
  • Metals and Alloys

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    Vakili, S. M., Zarei-Hanzaki, A., Anoushe, A. S., Abedi, H. R., Mohammad-Ebrahimi, M. H., Jaskari, M., Sohn, S. S., Ponge, D., & Karjalainen, L. P. (2020). Reversible dislocation movement, martensitic transformation and nano-twinning during elastic cyclic loading of a metastable high entropy alloy. Acta Materialia, 185, 474-492. https://doi.org/10.1016/j.actamat.2019.12.040