High-Throughput Phase Screening and Laser-Directed Energy Deposition of Ti-Ni-Nb Gradient Alloys

This work presents an integrated directed energy deposition (DED) approach utilizing a multi-powder feeder with real-time continuously variable composition functionality, a multi-powder mixer and a multi-powder nozzle to fabricate Ti-Ni-Nb gradient alloys with controlled compositional variations. The high-throughput methodology enables rapid alloy design and optimization by allowing precise manipulation of chemical composition and phase structures within a single deposited track. The EDS analysis confirms a gradual increase in titanium content, a nearly constant nickel content and a decrease in niobium along the scanning path, aligning with the expected powder-feeding trends. X-ray diffraction (XRD) analysis further reveals a phase transition from niobium-rich intermetallic compounds (NbNi4, Nb8Ni) at the beginning of the deposition to titanium-rich phases (Ti, Ti2Ni) at the end, demonstrating the ability to tailor phase distributions through real-time composition control. This high-throughput methodology enables rapid alloy design and optimization by integrating theoretical predictions with experimental phase screening. This study establishes a novel framework for the rapid discovery and optimization of functionally graded materials, paving the way for advanced applications in aerospace, biomedical implants and high-performance structural components.