Microstructure of nickel-based superalloy fabricated by selective laser melting in vacuum

Naoko Sato, Shizuka Nakano, Toshiki Nagahari, Taigi Nagoya, Koji Kakehi

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

Ni-based superalloy samples fabricated by selective laser melting (SLM) in inert gas are known to have lower creep ductility than cast and wrought one. The cause is thought to be due to oxide contamination from the powder surface and the SLM-specific microstructure. In this study, we evaluated the structure of the alloy 718 fabricated by SLM in a vacuum atmosphere that can be expected to suppress oxygen contamination and control the crystal orientation by decreasing the cooling rate. As a result, the microstructure of the samples fabricated by SLM in vacuum exhibits a layered structure, which is composed of a dendrite layer parallel to the building direction and the boundary, and the total thickness corresponds to the stacking thickness. On the other hand, the thickness of the top layer was more than double the additive layer thickness. From these results, the layered structure was formed by a heat-affected layer immediately below the melted part and a dendrite layer formed by melting.

Original languageEnglish
Pages (from-to)121-124
Number of pages4
JournalFuntai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy
Volume67
Issue number3
DOIs
Publication statusPublished - 2020
Externally publishedYes

Keywords

  • Microstructure
  • Nicked-based superalloy
  • Process atmosphere
  • Selective laser melting

ASJC Scopus subject areas

  • Mechanical Engineering
  • Industrial and Manufacturing Engineering
  • Metals and Alloys
  • Materials Chemistry

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