Ultrahard BCC-AlCoCrFeNi bulk nanocrystalline high-entropy alloy formed by nanoscale diffusion-induced phase transition

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

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Author(s)

  • Junjie Wang
  • Zongde Kou
  • Shu Fu
  • Shangshu Wu
  • Sinan Liu
  • Mengyang Yan
  • Zhiqiang Ren
  • Di Wang
  • Zesheng You
  • Si Lan
  • Horst Hahn
  • Tao Feng

Detail(s)

Original languageEnglish
Pages (from-to)29-39
Journal / PublicationJournal of Materials Science and Technology
Volume115
Online published21 Jan 2022
Publication statusPublished - 10 Jul 2022

Abstract

In the current work, the BCC-AlCoCrFeNi bulk nanocrystalline high-entropy alloy (nc-HEA) with ultra-high hardness was formed by nanoscale diffusion-induced phase transition in a nanocomposite. First, a dual-phase Al/CoCrFeNi nanocrystalline high-entropy alloy composite (nc-HEAC) was prepared by a laser source inert gas condensation equipment (laser-IGC). The as-prepared nc-HEAC is composed of well-mixed FCC-Al and FCC-CoCrFeNi nanocrystals. Then, the heat treatment was used to trigger the interdiffusion between Al and CoCrFeNi nanocrystals and form an FCC-AlCoCrFeNi phase. With the increase of the annealing temperature, element diffusion intensifies, and the AlCoCrFeNi phase undergoes a phase transition from FCC to BCC structure. Finally, the BCC-AlCoCrFeNi bulk nc-HEA with high Al content (up to 50 at.%) was obtained for the first time. Excitingly, the nc-HEAC (Al-40%) sample exhibits an unprecedented ultra-high hardness of 1124 HV after annealing at 500 °C for 1 h. We present a systematic investigation of the relationship between the microstructure evolution and mechanical properties during annealing, and the corresponding micro-mechanisms in different annealing stages are revealed. The enhanced nanoscale thermal diffusion-induced phase transition process dominates the mechanical performance evolution of the nc-HEACs, which opens a new pathway for the design of high-performance nanocrystalline alloy materials.

Research Area(s)

  • Composites, Diffusion-induced phase transition, High-entropy alloy, Inert gas condensation, Mechanical, Nanocrystalline

Citation Format(s)

Ultrahard BCC-AlCoCrFeNi bulk nanocrystalline high-entropy alloy formed by nanoscale diffusion-induced phase transition. / Wang, Junjie; Kou, Zongde; Fu, Shu; Wu, Shangshu; Liu, Sinan; Yan, Mengyang; Ren, Zhiqiang; Wang, Di; You, Zesheng; Lan, Si; Hahn, Horst; Wang, Xun-Li; Feng, Tao.

In: Journal of Materials Science and Technology, Vol. 115, 10.07.2022, p. 29-39.

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