Transmission electron microscopy characterization of dislocation structure in a face-centered cubic high-entropy alloy Al0.1CoCrFeNi

X. D. Xu, P. Liu, Z. Tang, A. Hirata, S. X. Song, T. G. Nieh, P. K. Liaw, C. T. Liu, M. W. Chen

Research output: Contribution to journalArticle

39 Citations (Scopus)

Abstract

Structural characterization of dislocations and dislocation reactions in a face-centered cubic high entropy alloy was conducted using the state-of-the-art spherical aberration corrected transmission electron microscopy. We experimentally measured the stacking fault energy of the high entropy alloy from the atomic images and diffraction contrast of dislocation cores. The low stacking fault energy results in widely dissociated dislocations and extensive dislocation reactions, which leads to the formation of immobile Lomer and Lomer-Cottrell dislocation locks. These dislocation locks act as both dislocation barriers and sources and are responsible for the significant work hardening with a large hardening rate in the alloy. Based on the atomic-scale characterization and classical dislocation theory, a simple equation was derived to describe the work hardening behavior of the high entropy alloy in the early-stage of plastic deformation.

Original languageEnglish
Pages (from-to)107-115
Number of pages9
JournalActa Materialia
Volume144
DOIs
Publication statusPublished - 2018 Feb 1

Keywords

  • Dislocation core
  • Dislocation reaction
  • High entropy alloy
  • Transmission electron microscopy
  • Work hardening

ASJC Scopus subject areas

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

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