On the role of the preheat temperature in electron-beam powder bed fusion processed IN718
File(s)
Published version
Author(s)
Adomako, Nana Kwabena
Haines, Michael
Haghdadi, Nima
Primig, Sophie
Type
Journal Article
Abstract
Process parameters optimization in additive manufacturing (AM) is usually required to unlock superior properties, and this is often facilitated by modeling. In electron beam powder bed fusion (E-PBF), the preheat temperature is an important parameter to be optimized as it significantly influences the microstructure and properties. Here we compare the effect of two preheat temperatures (1000 and 950°C, above and below δ-phase solvus temperature) on the microstructural evolution of E-PBF IN718 Ni-based superalloy. Using thermal and thermo-kinetic modeling, we predict microstructural changes and compare them with experimental findings. A decrease of only 50°C in the preheat temperature has a low impact on the solidification microstructure with a slight reduction in columnar grain width. In the solid-state, higher preheating causes intergranular δ-phase precipitation, contributing to a higher γ" precipitation potential, formation of co-precipitates, and higher hardness. The lower preheat temperature induces intergranular and intragranular δ-phase precipitation, reducing the γ" precipitation potential and hardness. The chemical composition of γ' and γ" is largely unaffected by the preheat temperature variation. These insights underscore the importance of preheat temperature optimization in microstructure design and property control during E-PBF.
Date Issued
2024-12
Date Acceptance
2024-08-28
Citation
Additive Manufacturing Letters, 2024, 11
ISSN
2772-3690
Publisher
Elsevier
Journal / Book Title
Additive Manufacturing Letters
Volume
11
Copyright Statement
© 2024 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
License URL
Identifier
http://dx.doi.org/10.1016/j.addlet.2024.100238
Publication Status
Published
Article Number
100238
Date Publish Online
2024-08-31