Thermal cycling effects on the local microstructure and mechanical properties in wire-based directed energy deposition of nickel-based superalloy

Florian Pixner, Fernando Gustavo Warchomicka, Marta Lipińska, Simon Elmiger, Clemens Jechtl, Peter Auer, Florian Kerem Riedlsperger, Ricardo Henrique Buzolin, Josef Domitner, Małgorzata Lewandowska, Norbert Enzinger

Research output: Contribution to journalArticlepeer-review

Abstract

In additive manufacturing, intrinsic heat treatments take place during deposition that affect the properties of AM-structures. In this work, the influence of thermal cycling on the local microstructure and mechanical properties of nickel-based superalloy in wire-based electron beam directed energy deposition (EB-DED) was investigated. Structures were fabricated using a continuous deposition strategy (CDS) and discontinuous interpass cooling strategy (ICS) revealing changes in thermal profiles, time-temperature history, and microstructure. An altered morphology along the build-up height and interdendritic zones enriched in Nb are formed. Nb and Mo did not show a clear trend of segregation along the build-up height. Lower fractions of the Laves phase and MCs are found for both configurations. Differences between deposition strategies and locations within AM-structures are found for the γ" and δ phase. The higher Nb content in the interdendritic zone promotes the precipitation of γ" and δ phase by shortening the aging times compared to wrought materials. The longer deposition times of ICS favour the precipitation of fine γ" in the interdendritic zone throughout the deposition height. In contrast, the short deposition time of CDS leads to an increase in temperature and a heterogeneous distribution of γ" along the height, i.e. coarsening of the γ" followed by a dissolution along the built-up height. The microstructural changes correlate with the mechanical properties. Structures fabricated with ICS exhibit homogeneous mechanical properties throughout, while the graded microstructure of CDS results in graded mechanical properties and decreasing strength throughout.

Original languageEnglish
Article number104066
JournalAdditive Manufacturing
Volume83
DOIs
Publication statusPublished - 5 Mar 2024

Keywords

  • Electron beam directed energy deposition
  • Nickel-based superalloy
  • Thermal management
  • Wire-based directed energy deposition

ASJC Scopus subject areas

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

Fields of Expertise

  • Advanced Materials Science

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