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arXiv · 2602.15729

Revealing 3D Strain and Carbide Architectures in Additively Manufactured Ni Superalloys

James A. D. Ball·David M. Collins·Yuanbo T. Tang·Jonathan P. Wright·Can Yildirim·Julia Richter·Yunhui Chen
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Abstract

Fast directional solidification during Laser Additive Manufacturing (LAM) produces a complex microstructure in nickel-based superalloys, comprising columnar grains with cellular sub-grain structures and carbides. Using non-destructive Scanning 3D X-ray Diffraction (S3DXRD), we reveal spatially complex orientation and intergranular strain relationships that couple strongly to processing-induced cellular sub-grain networks and a primary cubic metal carbide (MC) phase. We have examined 3D orientation and elastic strain tensor fields across 82 $γ$ grains together with the spatial distribution of over 37,000 MC carbides in an ABD-900AM alloy sample manufactured by the Directed Energy Deposition (DED) LAM process. Carbides are spatially associated with the cellular sub-grain network with a weak but present orientation relationship with their parent $γ$ grains. The MC carbides, known to be Ti, Ta and Nb rich, form in regions of high solute segregation, resulting in a significant volumetric lattice parameter patterning in the associated $γ$ phase regions. These chemically distinct solute-rich regions possess a higher associated elastic modulus compared to intercellular regions and determine the local residual stress patterning. These results provide the first non-destructive 3D study of the relationship between rapid solidification-induced segregation, deformation heterogeneity and carbide architectures in an additively manufactured Ni-based superalloy. The insights provide crucial detail to rationalise LAM process parameter optimisation and the coupled spatially governed structural performance.

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James A. D. Ball, David M. Collins, Yuanbo T. Tang, Jonathan P. Wright, Can Yildirim, Julia Richter, Yunhui Chen. 2026-02-17. Revealing 3D Strain and Carbide Architectures in Additively Manufactured Ni Superalloys. https://arxiv.org/abs/2602.15729

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