Additive Fertigung von Nickelbasissuperlegierungen: Rissbildung, Gefügeanalyse und Prozessoptimierung

Translated title of the contribution: additive manufacturing of nickel-base superalloys: crack formation, microstructural analysis and process optimization

Research output: ThesisMaster's Thesis


Due to the excellent high-temperature properties of nickel-base superalloys and near-net-shape fabrication using laser beam powder bed fusion (LB-PBF), additive manufacturing of these superalloys is of great interest to the industry. However, γ'-strengthened nickel-based alloys are considered difficult to weld and susceptible to cracking, which directly affects LB-PBF due to its similarity to the welding process. In this thesis, two difficult-to-weld nickel-base superalloys were investigated, and the corresponding samples were produced by LB-PBF. For the first alloy, NiBas1, a full factorial experimental design of 48 specimens was used. The process parameters of laser energy, scan speed and scan distance were varied. For the second alloy, NiBas2, the three best process parameters of the first alloy variant were optimized and 21 additional samples were produced. Statistical tests were used to investigate the influence of the process parameters on sample porosity and the scan distance was found to be the most influential factor. Light microscopic examinations were applied to the ground samples to analyze them in terms of microstructure, crack formation and component density. The influence of hot isostatic pressing (HIP) on porosity and crack growth was also investigated. In order to obtain information about the compositions, the samples were analyzed by X-ray diffraction and in-situ synchrotron experiments. Furthermore, detailed chemical analyses were performed using energy dispersive X-ray spectroscopy (EDX) in scanning electron microscope and scanning transmission electron microscope to determine differences between the matrix and crack environment. Thus, several factors, for example an increased Ti content along the cell walls and topologically closed packed phases, could be identified as the cause of cracking. However, γ'-phases could be excluded as crack initiation. In the future, the obtained knowledge can be used to reduce the cracking susceptibility of difficult-to-weld nickel-base superalloys and to fabricate defect-free components using LB-PBF.
Translated title of the contributionadditive manufacturing of nickel-base superalloys: crack formation, microstructural analysis and process optimization
Original languageGerman
Awarding Institution
  • Montanuniversität
  • Keckes, Jozef, Supervisor (internal)
Award date1 Jul 2022
Publication statusPublished - 2022

Bibliographical note

embargoed until 18-05-2027


  • laser beam powder bed fusion
  • nickel base superalloys
  • defects
  • cracks

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