3D Characterization of the Columnar-to-Equiaxed Transition in Additively Manufactured Inconel 718

Conference · Sat Aug 01 00:00:00 EDT 2020

DOI:https://doi.org/10.1007/978-3-030-51834-9_97· OSTI ID:1659558

Polonsky, Andrew ^[1]; Raghavan, Narendran  ^[2]; Echlin, McLean ^[1]; Kirka, Michael  ^[2]; Dehoff, Ryan  ^[2]; Pollock, Tresa ^[1]

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1. University of California Santa Barbara
2. ORNL

Additive manufacturing (AM) provides enormous processing flexibility, enabling novel part geometries and optimized designs. Access to a local heat source further permits the potential for local microstructure control on the scale of individual melt pools, which can enable local control of part properties. In order to design tailored processing strategies for target microstructures, models predicting the columnar-to-equiaxed transition must be extended to the high solidification velocities and complex thermal histories present in AM. Here, we combine 3D characterization with advanced modeling techniques to develop a more complete understanding of the solidification process and evolution of microstructure during electron beam melting (EBM) of Inconel 718. Full calibration of existing microstructure prediction models demonstrates the differences between AM processes and more conventional welding techniques, underlying the need for accurate determination of key parameters that can only be measured directly in 3D. The ability to combine multisensor data in a consistent 3D framework via data fusion algorithms is essential to fully leverage these advanced characterization approaches. Thermal modeling provides insight on microstructure development within isolated solidification events and demonstrates the role of Marangoni effects on controlling solidification behavior.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1659558
• Resource Relation: Conference: Superalloys 2021 - Seven Springs, Pennsylvania, United States of America - 9/12/2021 4:00:00 AM-
• Country of Publication: United States
• Language: English