Intermediate Layer in Titanium/Steel Dissimilar Welding: A Review

Dissimilar metal joints comprising titanium and steel are widely utilized in industrial fields. To mitigate the potential deterioration of welded joints resulting from the formation of brittle intermetallic compounds (IMCs) due to the direct contact between titanium and steel, an intermediary metal layer is typically employed during the welding process to prevent or restrict the generation of IMCs and thereby realize joints with superior mechanical properties. This study presents a comprehensive analysis of literature studies and technical processes pertaining to titanium/steel welding over the last decade. It provides a systematic review of the research progress in the dissimilar metal welding of titanium/steel systems with a particular focus on the utilization of intermediate layer metals. In addition, it discusses the existing challenges in the field of titanium/steel dissimilar metal welding in this area. Finally, this review critically analyzes emerging strategies for dissimilar material joining and proposes that in situ high‐entropy alloying of welded joints via fusion welding processes, guided by entropy design principles, represents a transformative pathway for next‐generation heterogeneous material welding technologies.