Microstructural Development in As Built and Heat Treated IN625 Component Additively Manufactured by Laser Powder Bed Fusion

Authors

Holden Hyer, University of Central Florida
Ryan Newell, Aerojet Rocketdyne
Dan Matejczyk, Aerojet Rocketdyne
Sinsar Hsie, Aerojet Rocketdyne
Mason Anthony, Aerojet Rocketdyne
Le Zhou, Marquette UniversityFollow
Cathy Kammerer, Aerojet Rocketdyne
Yongho Sohn, University of Central Florida

Document Type

Article

Publication Date

2-2021

Publisher

Springer

Source Publication

Journal of Phase Equilibria and Diffusion

Source ISSN

1547-7037

Abstract

The RL10 engine program is exploring the use of IN625 Ni-base superalloy components that are additively manufactured using laser powder bed fusion (LPBF). IN625 alloy powders are commercially available for LPBF to produce dense, complex parts/components. In this study, IN625 components, with both simple and complex geometries with overhangs, were manufactured via LPBF, and subjected to a heat-treatment consisting of a stress relief, hot isostatic pressing (HIP), and a solution anneal. The microstructure was examined with optical, scanning electron, and transmission electron microscopy. Changes in phase constituents and microstructure were documented as a function of heat treatment and component geometry (i.e., bulk section built on support structure versus thin, overhang section built on top of the previous powder bed). The as-built microstructural features included large columnar grains, a sub-grain cellular-solidification structure, approximately ~ 1 µm in diameter, and solute enriched cell boundaries decorated with A₂B Laves phases. After heat treatment, the bulk section consisted of recrystallized equiaxed grains with annealing twins, and the sub-grain cellular-solidification structure was found to be completely dissolved. However, in the thin, overhang section, the sub-grain cellular-solidification structure persisted within columnar grain structure, which exhibited no recrystallization. An alternate HIP cycle with a higher temperature was employed to produce desired microstructure (i.e., recrystallized grains without sub-grain cells and Laves phases) in components with geometrical complexity for successful testing of RL10 engine.

Comments

Accepted version. Journal of Phase Equilibria and Diffusion, Vol. 42, (February 2021): 14-27. DOI. © 2021 Springer. Used with permission.

Recommended Citation

Hyer, Holden; Newell, Ryan; Matejczyk, Dan; Hsie, Sinsar; Anthony, Mason; Zhou, Le; Kammerer, Cathy; and Sohn, Yongho, "Microstructural Development in As Built and Heat Treated IN625 Component Additively Manufactured by Laser Powder Bed Fusion" (2021). Mechanical Engineering Faculty Research and Publications. 280.
https://epublications.marquette.edu/mechengin_fac/280