Investigation by Numerical Simulation of Transition Alloys in WAAM Dissimilar Joints between Steel and Aluminum

The welding of dissimilar non-ferrous metals presents considerable challenges, primarily due to the propensity for the formation of brittle intermetallic compounds, which can severely compromise the mechanical integrity of the joint. This study investigates the metallurgical interaction between steel and aluminum by introducing a transition material—either the nickel-based alloy UNS N06625 or copper—applied via the Wire Arc Additive Manufacturing (WAAM) process. To support this investigation, computational simulations were carried out using the Simufact Welding® software suite. The numerical analysis focused on evaluating the thermal and mechanical behavior of the component prior to material deposition. Key simulation outputs included predictions of metallurgical dilution, phase transformation tendencies, residual stress distribution, and dimensional distortion in the fabricated structure. The results of this study provide a comprehensive understanding of the deposition behavior and compatibility of dissimilar materials when a transition joint composed of UNS N06625 or copper is employed between steel and aluminum substrates. Moreover, the simulation-based approach offers valuable predictive insights into the resultant mechanical and structural properties of components produced through advanced welding-based additive manufacturing techniques.