New Ti–6Al–7Nb–0.3Y Alloy for Laser Powder Bed Fusion of Patient–Specific Biomedical Implants: Ultrasonic Atomization and Characterization

A Ti–6Al–7Nb–0.3Y spherical powder was produced by ultrasonic atomization (UA), and its < 63 µm (d50 ≈ 53 µm) and 63–125 µm (d50 ≈ 82 µm) fractions were characterized for laser powder-bed fusion (LPBF) of patient–specific biomedical implants. Both fractions show near-ideal sphericity (1.01) with no satellites or internal pores, flow times of 26.8–28.0 s/50 g and bulk densities of 2.35–2.45 g/cm3 (51–53% of true density), matching commercial powder-bed feedstocks. XRD revealed only hexagonal α(α′)-Ti with a microstrain of 0.45–0.55%. Nanoindentation showed a hardness of 4.55–4.90 GPa, exceeding that of laser-powder-bed-fused Ti–6Al–4V (3.66 GPa), and an elastic modulus of 119–148 GPa on rigidly supported particles. Simultaneous thermal analysis showed stability up to 450 °C in all atmospheres, oxidation in air above 720 °C (Ea ≈ 160–170 kJ/mol) and mass gains at 1195 °C of 23.2–25.7% (air), 4.9–6.8% (N2) and 1.7–2.1% (Ar). The Ti–6Al–7Nb–0.3Y powder contains 0.69–0.74 wt.% Oxygen, far beyond the scavenging capacity of the retained 0.11–0.12 wt.% Yttrium, as well as 0.09–0.12 wt.% Nitrogen and 0.013–0.015 wt.% Hydrogen.