Pulse Duration and Wavelength Effects on the Surface Topography of Direct Laser Interference Patterning Treated Titanium Specimen

With rising prevalence of bone and skeletal diseases around the world, combatting implant failure through novel approaches has become a growing area of research. A novel way to produce tailored implants is additive manufacturing, which offers unprecedented design flexibility. On the other hand, the osseointegration of such implants can be optimized by applying periodic micro-textures on the surface, using laser-based techniques. 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 line-like micro textures on additively manufactured Ti-13Nb-13Zr parts. Using different solid-state lasers, the effect of pulse durations in the nanosecond to femtosecond regime and laser wavelengths from the ultraviolet to near infrared spectrum on the micro texture topography is reported. For each wavelength and pulse duration, laser parameters are varied systematically. The surface topography of the specimens is characterized through scanning-electron microscopy, and surface roughness is measured with confocal microscopy. Interaction with nanosecond pulses is characterized by melting, resulting in mostly smooth textures, whereas picosecond and femtosecond pulses produce hierarchical textures with laser-induced periodic surface structures.