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Application of Finite Element, Phase-field, and CALPHAD-based Methods to Additive Manufacturing of Ni-based Superalloys

Published

Author(s)

Trevor Keller, Greta Lindwall, Supriyo Ghosh, Li Ma, Brandon M. Lane, Fan Zhang, Ursula R. Kattner, Eric Lass, Yaakov S. Idell, Maureen E. Williams, Andrew J. Allen, Jonathan E. Guyer, Lyle E. Levine

Abstract

Numerical simulations are used in this work to investigate aspects of microstructure and microsegregation during rapid solidification of a Ni-based superalloy in a laser powder bed fusion additive manufacturing process. Thermal modeling by finite element analysis simulates the laser melt pool, with surface temperatures in agreement with in situ thermographic measurements on Inconel 625. Geometric and thermal features of the simulated melt pools are measured and used in subsequent mesoscale simulations. Solidification in the melt pool is simulated on two length scales. Phase-field simulations, using Ni–Nb as a binary analogue to Inconel 625, produced microstructures with primary cellular/dendritic arm spacings in agreement with measured spacings in experimentally observed microstructures. Microsegregation between secondary dendrite arms is calculated using the Scheil-Gulliver solidification model and DICTRA software.1 These data are used to compare thermodynamic driving forces for nucleation against experimentally observed precipitates identified by electron and X-ray diffraction analyses. Our analysis indicates the formation of precipitates in enriched interdendritic regions for either of two recommended heat treatment temperatures: stress relief at 1143 K or homogenization at 1423 K.
Citation
Acta Materialia
Volume
139

Keywords

Additive manufacturing, Finite element analysis (FEA), CALPHAD, Phase-field simulations, Microsegregation

Citation

Keller, T. , Lindwall, G. , Ghosh, S. , Ma, L. , Lane, B. , Zhang, F. , Kattner, U. , Lass, E. , Idell, Y. , Williams, M. , Allen, A. , Guyer, J. and Levine, L. (2017), Application of Finite Element, Phase-field, and CALPHAD-based Methods to Additive Manufacturing of Ni-based Superalloys, Acta Materialia, [online], https://doi.org/10.1016/j.actamat.2017.05.003 (Accessed May 14, 2021)
Created September 21, 2017, Updated November 10, 2018