Multi-material additive manufacturing enables functionally integrated components by combining dissimilar metallic alloys within single structures, addressing performance limitations of homogeneous materials in demanding applications. Among wire-based directed energy deposition processes, laser wire additive manufacturing offers precision, process control, and material efficiency particularly suited for high-performance applications. However, interfacial incompatibilities, intermetallic compound formation, thermal expansion mismatch, and insufficient wettability, pose significant fabrication challenges. This review systematically examines wire-laser-based multi-material additive manufacturing through comprehensive literature analysis. The study first presents established single-material feedstocks organized by alloy family, then analyzes bimetallic material combinations that have received research attention. Findings reveal that stainless steel-Inconel pairings dominate current research due to favorable metallurgical compatibility, demonstrating technical maturity through epitaxial grain growth and defect-free interfaces. However, the majority of material combinations appear in only a few publications, indicating critically limited research density. Analysis identifies key interfacial challenges and mitigation strategies including functionally graded transitions and buffer layers. Significantly, numerous industrially relevant material pairings remain underexplored despite technical feasibility and application potential. Specifically, combinations such as tool steel-copper alloys, aluminum bronze-structural steels, maraging steel-cobalt alloys, and Stellite-Inconel systems could unlock breakthrough capabilities in wear-resistant tooling, thermal management, and high-temperature components. This research gap mapping establishes foundation for advancing wire-laser multi-material manufacturing from narrow laboratory demonstration toward mature industrial technology addressing diverse high-performance applications.

Keywords

Directed energy deposition, Wire-based additive manufacturing, Wire-laser energy deposition, Bimetallic combinations, Characteristics and applications