Study on the Microstructure, Properties, and Biocompatibility of Ti-35Nb-15Zr (at. %) Alloy Fabricated by Laser Powder Bed Fusion

This study employs 100 µm laser spot–based laser powder bed fusion (LPBF) to fabricate Ti-35Nb-15Zr (T3515) alloy, aiming to overcome the unmelted Nb particles and spattering defects inherent in small‑spot systems caused by Nb's high melting point, and to elucidate the regulatory role of volumetric energy density (VED) on microstructure and properties. Optimized power‑scanning speed coupling significantly reduces unmelted Nb (to 0.154%), promotes a uniform bimodal grain distribution (average 19.63 µm), and achieves a yield strength of 1258 MPa, elongation of 8.36%, and 28.96% higher wear resistance, along with a 3.5‑fold increase in productivity (relative density >99%, Ra <10 µm). Higher VED intensifies <001> texture but elevates magnetic susceptibility, aggravating MRI artifacts. Post‑treatments show that 250°C aging boosts elongation by 40% (to 10.58%) via stress relaxation; 450°C annealing induces α‑phase precipitation, raising hardness to 351.69 HV, yet also increases susceptibility; above the β‑transus, grain coarsening (to 28.26 µm) degrades both ductility and wear resistance. This work reveals how energy input governs grain size, Nb dissolution, and texture through melt‑pool dynamics.

Dr. Jun Zhou is an Assistant Professor and Master's Supervisor at Guangxi University's School of Mechanical Engineering. His research addresses welding metallurgy and powder bed fusion additive manufacturing, with emphasis on microstructural evolution, metallurgical reactions, and thermal processing–property relationships. He serves as Principal Investigator for three provincial research grants and has authored over 20 SCI-indexed papers. He also teaches two undergraduate core courses: Fundamentals of Materials Science and Engineering and Hydraulic Transmission.