Influence of Laser Texturing on Microstructure, Surface and Corrosion Properties of Ti-6Al-4V

We present the modification of Ti-6Al-4V surfaces with a diode end-pumped Nd:YVO4 laser by varying the distance between laser-produced micro(mu)-channels. We analyzed the influence of laser texturing on the morphology, microstructure, surface and corrosion properties of Ti-6Al-4V. SEM imaging reveals a characteristic mu-channel pattern with different scan line separations, while electron backscatter diffraction (EBSD) indicates that laser texturing with the current parameters influences the microstructure up to 2 mu m deep with the most significant influence at the tips, where melting and rapid solidification occur. The Vickers hardness test indicates a surface hardening effect of the laser-textured compared to the as-received Ti-6Al-4V surfaces. The XPS analysis showed that the oxide layer on the laser-textured samples was considerably thicker compared to the as-received sample, at 20 and 7 nm, respectively. We observed that the wettability was strongly correlated with the scan line separation. The results show increased hydrophobicity with increased scan line separation. The corrosion resistance was improved for laser-textured surfaces compared to the as-received surface and increased with the scan line separation.