3D ink-extrusion additive manufacturing of CoCrFeNi high-entropy alloy micro-lattices

Christoph Kenel*, Nicola P.M. Casati, David C. Dunand

*Corresponding author for this work

Research output: Contribution to journalArticle

5 Scopus citations

Abstract

Additive manufacturing of high-entropy alloys combines the mechanical properties of this novel family of alloys with the geometrical freedom and complexity required by modern designs. Here, a non-beam approach to additive manufacturing of high-entropy alloys is developed based on 3D extrusion of inks containing a blend of oxide nanopowders (Co 3 O 4 + Cr 2 O 3 + Fe 2 O 3 + NiO), followed by co-reduction to metals, inter-diffusion and sintering to near-full density CoCrFeNi in H 2 . A complex phase evolution path is observed by in-situ X-ray diffraction in extruded filaments when the oxide phases undergo reduction and the resulting metals inter-diffuse, ultimately forming face-centered-cubic equiatomic CoCrFeNi alloy. Linked to the phase evolution is a complex structural evolution, from loosely packed oxide particles in the green body to fully-annealed, metallic CoCrFeNi with 99.6 ± 0.1% relative density. CoCrFeNi micro-lattices are created with strut diameters as low as 100 μm and excellent mechanical properties at ambient and cryogenic temperatures.

Original languageEnglish (US)
Article number904
JournalNature communications
Volume10
Issue number1
DOIs
StatePublished - Dec 1 2019

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ASJC Scopus subject areas

  • Chemistry(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Physics and Astronomy(all)

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