Effects of Deposition Sequence on Microstructural Formation in Additively Manufactured GRCop-42 / Alloy 718 Bimetallic Structures

Published

May 23, 2023

Author(s)

Andrew Iams, Tom Lienert, David Otazu, Monsuru Ramoni

Abstract

Although Cu-Cr-Nb alloys / superalloys bimetallic components for liquid rocket engine applications have been fabricated using additive manufacturing, a detailed understanding of their process-structure relation is currently lacking. To bridge this gap, GRCop-42 / Alloy 718 bimetallic structures were fabricated with two different deposition sequences, using powder feedstock with a laser-based directed energy deposition process. The deposition sequence resulted in significant variations in precipitate morphology, composition, and crystal structure within the GRCop-42, particularly at locations near the interface. When Alloy 718 was deposited first, dilution and convective mixing resulted in elevated Ni and Fe levels within the GRCop-42 deposit, which contributed to the formation of C14 (Cr, Ni, Fe)2Nb Laves and α-Cr phases. The anticipated C15 Cr2Nb precipitates were observed within the GRCop-42 material when the deposition sequence was reversed.

Citation

Additive Manufacturing Letters

Pub Type

Journals

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Keywords

Additive manufacturing, laser-based directed energy deposition, combustion chamber, GRCop-42, Laves phase

Citation

Iams, A. , Lienert, T. , Otazu, D. and Ramoni, M. (2023), Effects of Deposition Sequence on Microstructural Formation in Additively Manufactured GRCop-42 / Alloy 718 Bimetallic Structures, Additive Manufacturing Letters, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=936381 (Accessed October 1, 2025)