Abstract
Hybrid Additive Manufacturing (HAM) has recently gained significant attention as a method for producing multilayer and bimetallic structures. Alloy 625–CuNi bimetallic systems, in particular, are increasingly investigated for applications requiring excellent thermal conductivity, and tailored mechanical performance, such as in heat exchangers. In this study, a bimetallic Alloy 625 - CuNi structure was successfully fabricated using HAM combining Wire Arc Additive Manufacturing (WAAM) and Cold Spray (CS), leveraging the advantages of both processes. Various WAAM deposition routes were explored, and the molten pool behavior during fabrication was captured using a high-speed camera to better understand process stability and interlayer bonding. WAAM enabled rapid deposition with strong metallurgical bonding, while CS contributed refined microstructural features and reduced heat input in selected regions. The resulting multilayer architecture was systematically characterized using optical microscopy (OM), scanning electron microscopy (SEM), and X-ray diffraction (XRD) to evaluate microstructural evolution, phase constitution, and interlayer integrity. Microscale mechanical properties were assessed through nanoindentation to quantify hardness and modulus variations across individual layers.