Abstract

This study provides a systematic investigation into the combined effects of welding current (75–175 A) and wire feed rate (300–600 mm/min) on cracking behavior, solidification characteristics, and interfacial reactions during Gas Tungsten Arc Welding cladding of Aluminum 1100 onto SCM440 steel—a dissimilar material combination for which comprehensive microstructural analysis remains limited. The results reveal a clear transition from severe solidification cracking to crackfree clads as heat input increases, establishing 150–175 A as the threshold for molten pool stability. A coupled evaluation of dendrite arm spacing, hardness, and interfacial diffusion further highlights the sensitivity of Fe-rich IMC formation to feed-rate-controlled heat input. Dendrite arm spacing increases with current but decreases with feed rate, while EDS analysis confirms the formation of Fe-rich intermetallic phases consistent with diffusion-driven Al–Fe reactions. The integrated mapping of cracking, DAS, IMC chemistry, and bead geometry identifies 150 A with 500 mm/min as an optimal condition for producing defect-free and metallurgically stable aluminum–steel clads. These findings offer new insights into heat-input–controlled phase evolution and provide a practical framework for optimizing GTAW-based aluminum cladding on alloy steels.