Simultaneously enhancing strength and ductility of a high-entropy alloy via gradient hierarchical microstructures

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

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Author(s)

  • M. N. Hasan
  • Y. F. Liu
  • X. H. An
  • J. Gu
  • M. Song
  • Y. Cao
  • Y. S. Li
  • X. Z. Liao

Detail(s)

Original languageEnglish
Pages (from-to)178-195
Journal / PublicationInternational Journal of Plasticity
Volume123
Online published26 Jul 2019
Publication statusPublished - Dec 2019
Externally publishedYes

Abstract

Although many high-entropy alloys (HEAs) possess excellent mechanical properties, they are not exempt from the common dilemma of strength-ductility trade-off in most cases, which limits their potential applications. Herein, rotationally accelerated shot peening was used to introduce different gradient hierarchical microstructures, including gradients in twin and dislocation densities, and hierarchical nanotwin, into a CoCrFeNiMn HEA by adjusting the processing parameters. The resulting gradient structures and their effect on hardening behaviour and mechanical properties were systematically explored. Quantitative analysis indicates that deformation twinning, including hierarchical nanotwinning could be more important than dislocation slip in terms of their contribution to hardness and strain hardening capability, depending on the gradient structure profile. It was found that simultaneous improvement of strength and ductility can be achieved in a gradient structure with a thin deformed layer and an undeformed core. Based on our experimental results, we propose that a gradient structure with a largest possible strength difference between the surface layer and the undeformed core would maximize the strength-ductility synergy.

Research Area(s)

  • Gradient structure, Hierarchical nanotwin, High-entropy alloy, Mechanical properties, Rotationally accelerated shot peening

Citation Format(s)

Simultaneously enhancing strength and ductility of a high-entropy alloy via gradient hierarchical microstructures. / Hasan, M. N.; Liu, Y. F.; An, X. H.; Gu, J.; Song, M.; Cao, Y.; Li, Y. S.; Zhu, Y. T.; Liao, X. Z.

In: International Journal of Plasticity, Vol. 123, 12.2019, p. 178-195.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review