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Phase Composition and Phase Transformation of Additively Manufactured Nickel Alloy 718 AM Bench Artifacts

Published

Author(s)

Fan Zhang, Aaron Johnston-Peck, Lyle E. Levine, Michael Katz, Kil-Won Moon, Maureen E. Williams, Sandra W. Young, Andrew J. Allen, Olaf Borkiewicz, Jan Ilavsky

Abstract

Additive Manufacturing (AM) technologies offer unprecedented design flexibility but are limited by a lack of understanding of the material microstructure formed under their extreme and transient processing conditions and its subsequent transformation during post-build processing. As part of the 2022 AM Bench Challenge, sponsored by the National Institute of Standards and Technology, this study focuses on the phase composition and phase evolution of AM nickel alloy 718, a nickel-based superalloy, to provide benchmark data essential for the validation of computational models for microstructural predictions. We employed high-energy synchrotron X-ray diffraction, in situ synchrotron X-ray scattering, as well as high-resolution transmission electron microscopy for our analyses. The study uncovers critical aspects of the microstructure in its as-built state, its transformation during homogenization, and its phase evolution during subsequent aging heat treatment. Specifically, we identified secondary phases, monitored the dissolution and coarsening of microstructural elements, and observed the formation and stability of γ' and γ" phases. The results provide the rigorous benchmark data required to understand the atomic and microstructural transformations of AM nickel alloy 718, thereby enhancing the reliability and applicability of AM models for predicting phase evolution and mechanical properties.
Citation
Integrating Materials and Manufacturing Innovation
Volume
12
Issue
4

Keywords

Benchmark, Additive Manufacturing, Nickel-based super alloy, X-ray diffraction, Transmission electron microscopy, Microstructure, Atomic structure, Laser powder bed fusion

Citation

Zhang, F. , Johnston-Peck, A. , Levine, L. , Katz, M. , Moon, K. , Williams, M. , Young, S. , Allen, A. , Borkiewicz, O. and Ilavsky, J. (2024), Phase Composition and Phase Transformation of Additively Manufactured Nickel Alloy 718 AM Bench Artifacts, Integrating Materials and Manufacturing Innovation, [online], https://doi.org/10.1007/s40192-023-00338-y, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=956742 (Accessed April 15, 2024)
Created February 5, 2024, Updated February 14, 2024