Mechanical and corrosion properties of CoCrFeNiTi-based high-entropy alloy additive manufactured using selective laser melting

Tadashi Fujieda, Meichuan Chen, Hiroshi Shiratori, Kosuke Kuwabara, Kenta Yamanaka, Yuichiro Koizumi, Akihiko Chiba, Seiichi Watanabe

Research output: Contribution to journalArticlepeer-review

18 Citations (Scopus)

Abstract

The effectiveness of applying selective laser melting (SLM) to a CoCrFeNiTi-based high-entropy alloy was compared with that of using electron beam melting (EBM). The higher solidification rate during SLM promoted a fine uniform microstructure with no visible segregation, which led to superior tensile properties (yield strength: 773.0 ± 4.2 MPa, ultimate tensile strength: 1178.0 MPa, elongation: 25.8 ± 0.6%) and a higher pitting potential (0.88 ± 0.03 V versus Ag/AgCl in a 3.5% NaCl solution at 353 K) in comparison to the EBM specimens (743.4 ± 11.6, 932.2 ± 4.8 MPa, 4.0 ± 0.2%, and 0.50 ± 0.04 V versus Ag/AgCl, respectively). The effect of a solution treatment on the tensile properties and pitting-corrosion resistance of the SLM specimens was then examined. The effect of the solution treatment on these properties depended on the cooling method used during the treatment. In particular, the tensile properties and pitting-corrosion resistance improved as a result of water quenching. On the other hand, the properties of the solution-treated specimens depended on the size and volume fraction of very fine-ordered particles, with diameters of tens of nanometers that contained Ni and Ti. The as-built and solution-treated SLM specimens exhibited excellent tensile strength and exceptional pitting-corrosion resistance; they had higher tensile strength and pitting-corrosion resistance than the conventional high-corrosion-resistant alloys.

Original languageEnglish
Pages (from-to)412-420
Number of pages9
JournalAdditive Manufacturing
Volume25
DOIs
Publication statusPublished - 2019 Jan

Keywords

  • Additive manufacturing
  • High-entropy alloys
  • Ordered particles
  • Selective laser melting
  • Solution-treatment

ASJC Scopus subject areas

  • Biomedical Engineering
  • Materials Science(all)
  • Engineering (miscellaneous)
  • Industrial and Manufacturing Engineering

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