Study of the effect of process parameters and heat treatment on the formation and evolution of directed energy deposition of IN718-CuCrZr interface

Official URL: https://dx.doi.org/10.1002/adem.202500773

Joining dissimilar materials as coatings or multimaterial compounds remains challenging due to mismatches in atomic orientation, microstructure, and thermal properties. The laser powder directed energy deposition (LP-DED) process is an additive manufacturing (AM) technique capable of producing bimetallic or functionally graded materials for coatings or heavy-duty applications. However, understanding interface characteristics in response to process parameters and heat treatment is critical for evaluating structural integrity. This study investigates the Inconel 718/CuCrZr interface and examines the effects of process parameters and heat treatment on microstructural evolution. The optimized bimetallic sample is free of cracks and excessive porosity, indicating a successful deposition. The results show that Inconel 718 acts as a thermal barrier during CuCrZr deposition due to its low thermal conductivity, significantly influencing grain structure and hardness. To achieve a homogeneous interface, four heat treatment strategies are used, and their effects on microstructure and hardness are analyzed. These strategies induce major changes in joint properties, demonstrating that an appropriate heat treatment improves hardness, interface characteristics, and microstructural uniformity. The findings confirm that achieving the desired interface properties for coatings or multimaterial production is possible through optimized process parameters and heat treatment.