Optimizing process parameters for interfacial integrity in Cu–Ni bi-metallic additive manufacturing

Copper (Cu)-based alloys are often coupled with the Nickel (Ni)-based superalloys to form bi-metallic components with both high thermal and structural properties. Contemporary efforts focus around application of additive manufacturing (AM) methods, as conventional manufacturing (CM) routes can’t reproduce complex bi-metallic component designs. However, like CM components, they suffer from interfacial cracking, the origin of which is frequently linked to the copper presence in the crack regions. Literature highlights temperature of the melt pool and of the heat affected zone (HAZ) as the main driver for enhanced copper diffusion and its affinity to facilitate cracking. Intrinsically, AM process parameters are expected to be pivotal in controlling the temperature of the build and, hence, copper diffusion. In this work, we used process optimization to minimize the cracking through energy redistribution during the deposition and control of the melt pool dynamics of CuCrZr single tracks on Inconel 718 substrate. Our results show that process optimization has eliminated macro-scale cracking, while concurrently micro-cracks were still observed adjacent to the melt pool boundary. Crucially, these micro-cracks were successfully eliminated using further process optimization. This milestone sets the foundation for developing complex interfaces securing defect-free process parameters