Microstructure and compressive properties of 3D-extrusion-printed, aluminized cobalt-based superalloy microlattices

Hyeji Park, Heeman Choe, David C. Dunand*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Cobalt-based superalloy microlattices with γ/γ′ microstructure are manufactured by combining two additive methods: ink-extrusion 3D-printing and pack-cementation surface alloying. First, a microlattice green structure is 3D-printed at ambient temperature from inks comprised of Co3O4, NiO, and WO3 powders, an elastomeric binder and solvents. Organic removal followed by oxide reduction under Ar-5% H2, sintering and homogenization at 1250 °C lead to a metallic microlattice with dense struts with uniform γ (fcc)-Co–22Ni–8W (at.%) composition. Second, aluminum is deposited on the strut surfaces via pack-cementation at 1000 °C, diffused at 1300 °C through the strut volume to achieve a uniform composition (Co–20Ni–6W–10Al or Co–18Ni–5W–13Al, at.%), and precipitated during aging at 900 °C as γ′ precipitates within the γ matrix. The compressive strength, ductility and energy absorption of these γ/γ′ Co-based precipitation-strengthened microlattices is measured at ambient temperatures for two aging time (16 and 65 h) and found to be much superior to those of an unalloyed Co microlattice.

Original languageEnglish (US)
Article number141262
JournalMaterials Science and Engineering A
Volume815
DOIs
StatePublished - May 20 2021

Keywords

  • 3D-printing
  • Co-based superalloy
  • High-temperature application
  • Microlattice architecture
  • Pack-cementation

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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