Elucidating the challenges in the development and deployment of refractory complex concentrated alloys for additive manufacturing

The increasing demand for advanced materials with load-bearing capabilities in extremely high-temperature environments has brought considerable attention to the design and fabrication of novel refractory complex concentrated alloys. Despite the notable progress in design of customized alloys, there are still significant challenges regarding their processing and fabrication, highly limiting their exploitation. In this study, model non- equiatomic Nb-Ta based refractory complex concentrated alloys were created as potential materials with improved high-temperature stability and performance for space propulsion applications. Gas atomization was used for producing spherical pre-alloyed powders. Two different additive manufacturing techniques, i.e., laser powder bed fusion and cold spray were used to explore the manufacturing complexities of this novel alloy. The results highlight the importance of powder’s features on its processability by laser powder bed fusion and cold spray. High interstitial content, inhomogeneous microstructures, fractured and hollow particles, and the presence of microsegregation, led to embrittlement, and in case of cold spray, the wide particle size range of the feedstock resulted in undesired flowability, adversely affecting the processibility of the developed material. The obtained results provide valuable insights and recommendation for improving design, preparation, and fabrication of custom-designed refractory alloys for additive manufacturing.