| Abstract Scope |
Wire Arc Additive Manufacturing (WAAM) offers significant potential for fabricating large-scale multi-material structures; however, multi-material structures involving refractory and commercial alloys remain challenging due to mismatch in thermo-physical properties, diffusion behavior, intermetallic formation. This work presents a systematic investigation of WAAM-fabricated multi-material structures, including 90WNiFe–In625, Ti6Al4V–NbZr1, and TZM–NbZr1. Across all systems, defect-free interfaces with strong metallurgical bonding and minimal intermetallic formation were achieved. Interfacial microstructures were governed by diffusion-driven phase evolution and heat input conditions, significantly influencing hardness and mechanical performance. The 90WNiFe–In625 system exhibited superior ductility (up to ~49%) and strength (~618 MPa) under optimized heat input, while Ti6Al4V–NbZr1 demonstrated high strength (~567 MPa) with brittle fracture characteristics. In contrast, TZM–NbZr1 showed limited ductility due to porosity effects. These findings establish critical process–structure–property relationships for designing functionally graded WAAM structures for aerospace, nuclear and other extreme operating environments. |