Growth of Titania Nanotubes on Laser Powder Bed Fusion Printed Ti6Al4V ELI

The growth of electrochemically anodized titania nanotube (TiNT) arrays is strongly influenced by the microstructure of the underlying titanium substrate. In Laser Powder Bed Fusion (LPBF), this microstructure is governed by the processing parameters, yet the relationship between LPBF processing, microstructural evolution, electrochemical dissolution behavior, and TiNT growth remains poorly understood. In this study, Ti6Al4V ELI specimens were fabricated by systematically varying laser power, scan velocity, and layer thickness, followed by potentiostatic anodization to investigate their influence on TiNT formation. Electron backscatter diffraction revealed that increasing laser power refined the area-dominant α′ -martensitic laths, whereas increasing layer thickness promoted lath coarsening, and scan velocity produced comparatively minor changes. Electrochemical measurements, including open-circuit potential, linear sweep voltammetry, electrochemical impedance spectroscopy, and anodization current transients, demonstrated that finer lath microstructures exhibited higher electrochemical activity and lower charge-transfer resistance, resulting in accelerated nanotube growth. Consequently, TiNT length increased from 1.7 ± 0.1 to 8.8 ± 0.1 µ m with increasing laser power, whereas increasing layer thickness reduced nanotube length from 7.1 ± 0.2 to 3.0 ± 0.1 µ m. The results establish a direct process–microstructure–electrochemical kinetics–nanotopography relationship, demonstrating that LPBF process parameters can be strategically employed to tailor TiO 2 nanotube architectures.