With rising prevalence of bone and skeletal diseases around the world, combatting implant failure through novel approaches has become a growing area of research. Additive manufacturing can contribute to a solution by enabling an unprecedented design flexibility, quick prototyping and patient-specific construction. On the other hand, optimizing the interaction of bone cells with the implant surface can be improved through the additional application of tailored periodic microtextures on the implant surface. Laser-based microtexturing methods have shown to be a versatile tool for the fabrication of topographical elements on metal surfaces. In particular the technique of Direct Laser Interference Patterning (DLIP) offers both high throughput and the possibility to produce structures with small feature sizes. In this work, DLIP is applied to produce microstructures on additively manufactured Ti-13Nb-13Zr alloy. In particular, this work investigates the influence of the laser pulse duration and wavelength. For this purpose, solid-state lasers operating with pulses in the nanosecond-, picosecond- and femtosecond regime and with wavelengths in the near-infrared, visible and ultraviolet spectrum are used with a two-beam DLIP configuration, resulting in line-like surface patterns. In the nanosecond pulse regime, it was observed that melting effects play a significant role in the ablation process, resulting in mostly smooth textures. In case of the picosecond- and femtosecond regimes, laser-induced periodic surface structures (LIPSS) are observed alongside the DLIP pattern, and melting is significantly reduced compared to nanosecond textures. The influence of the used laser wavelength is most prominent in the picosecond regime, where it determines the LIPSS period [1]. By systematically varying laser parameters such as the number of pulses and the laser fluence, achievable texture roughness is estimated. The surface topography of the specimens was characterized through scanning-electron microscopy and surface roughness measured with confocal microscopy.

[1] Schell, F., Alamri, S., Hariharan, A., Gebert, A., Lasagni, A. F. and Kunze, T., “Fabrication of four-level hierarchical topographies through the combination of LIPSS and direct laser interference pattering on near-beta titanium alloy,” Materials Letters, 306, 130920, (2022).