Insights on Interface Features in 3D-Printed Multi-materials

Multi-material components, integrating the properties of different materials within a single product, represent a major innovation in Additive Manufacturing (AM). The multi-material approach exploits the unique characteristics of each material to enhance performance aspects such as mechanical strength, weight reduction, corrosion resistance, and thermal or electrical conductivity. However, integrating different metal alloys through AM remains challenging due to substantial differences in physical and metallurgical properties, which can compromise the quality and durability of multi-material interfaces. The study of interfaces in additively manufactured multi-material structures becomes thus crucial for understanding the mechanical, thermal, and chemical performance of the final component. This research aims to investigate the interfacial bonding mechanisms, defect formation, and property gradients that arise in additively manufactured multi-material samples obtained by coupling Ni-based, and Cu-based alloys using PBF-LB/M processes. Employing advanced characterization techniques (FEG-SEM, XRD, micro and nanoindentation and FEG-SEM in-situ tensile tests) coupled with CALPHAD-based simulations, the microstructural features and mechanical integrity of the interfacial regions were assessed. Results indicate that material properties and interface adhesion are influenced by printing parameters, deposition sequence of the alloys, intermixing effects at the interface region. Post-printing annealing treatments were evaluated to assess opportunities for thermal-stress relaxation. This study contributes to the development of high-performance multi-material AM components for applications ranging from automotive to aerospace, electronics, and medical devices.