Development of Grcop42/Copper-Inconel 718 multi material structure through laser powder bed usion for heat transfer application

The development of multi material structures using laser powder bed fusion (LPBF) technology by combining desired thermo-mechanical properties, offers significant potential for enhancing heat transfer applications, particularly in aerospace. This study focuses on the fabrication of pure Copper-Inconel 718 (Cu-IN718) and Copper alloy-In718 (GrCop42-IN718) multi-materials, by leveraging the high-temperature strength and thermal stability of IN718 with the great thermal conductivity of Cu and GrCop42. The integration of high-strength IN718 with high-thermal conductive Cu/GrCop42, aims to improve heat exchanging capabilities, specifically for advanced engineering applications. However, additive manufacturing of high-strength multi material interfaces remains challenging due to significant differences in their thermo-physical properties and week bonding and defects in interface. In this study, the effects of process parameters and the consequence of materials in layers or each layer on the interface properties of the LPBF’ed Cu-IN718 and GrCop42-IN718 were analyzed, and the process parameters were optimized to reach the good metallurgical bonding interface between Cu/GrCop42 and IN718. Through this research the interface microstructure characteristics, element distribution, phases in interface, thermal conductivity, and microhardness of these multi materials were investigated. The melting behavior, mixing of IN718 and Cu/GrCop42 elements and in-situ phases in interface, and formation mechanism of multi materials in different consequence of materials were discussed. The formation of interface characteristics is primarily driven by Marangoni convection, which enhances the mixing of IN718 and Cu/GrCop42 elements, facilitates the development of a stable transition layer at the interface, and enables a seamless transition between the two metal interfaces. Compared to IN718, the Cu-IN718 and GrCop42-IN718 multi material structures exhibited significantly enhanced thermal conductivity. These advancements open up and paves the way for the additive manufacturing of multi materials in next-generation aerospace structures.