Additive manufacturing of high-entropy alloys: Current status and challenges

Additive manufacturing (AM) of alloys has garnered substantial scientific and technological interest due to its applications in the manufacturing of structural components. High entropy alloys (HEAs) represent a novel class of structural materials that have received significant attention in the past two decades. AM methods such as laser powder bed fusion (LPBF) offer the capability to tailor the microstructures of alloys, facilitating the production of HEAs with tailored properties. The rapid advancements in this field necessitate an updated and comprehensive review on the design and production of HEAs specific to additive manufacturing. This review summarizes the relationships among processing parameters, microstructure, and resultant properties in AM-produced HEAs. Special attention is given to AM techniques, including powder bed fusion, directed energy deposition, and binder jet printing. This review extensively examines the effects of feedstock quality and processing parameters on the formation of metallurgical defects, as-built microstructure, mechanical behavior, and corrosion resistance of single-phase HEAs, multi-phase HEAs, and HEA matrix composites. Additionally, the applications of AM-produced HEAs, the challenges associated with their production via AM techniques, and future perspectives identified through a thorough literature survey are discussed.