| Abstract Scope |
Combustion chambers for liquid rocket engines are excellent candidates for additive manufacturing due to their multi-material design and complex internal geometries. These components are often fabricated using a Cu-Cr-Nb alloy, such as GRCop-42, for the internal liner and a superalloy as the structural jacket. Although GRCop-42 components have been fabricated using additive manufacturing, a detailed understanding of the process-structure relation is currently lacking. To bridge this gap, GRCop-42 / Alloy 718 bimetallic structures were fabricated with two different deposition sequences, using laser-based directed energy deposition. 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 macrosegregation resulted in elevated Ni and Fe levels within GRCop-42, which contributed to (Cr, Ni, Fe)2Nb Laves and α-Cr phase formation. The anticipated Cr2Nb precipitates were observed when the deposition sequence was reversed. |