Laser interference-treatment tunes surface states and corrosion behavior of additively manufactured near-beta Ti alloy

Near-beta titanium alloys are promising bone implant materials due to their low elastic modulus and good corrosion resistance. To optimize their surface properties, we apply direct laser interference patterning (DLIP) microtextures using nano (ns)- and picosecond (ps) pulses to an additively manufactured Ti-13Nb-13Zr alloy. It was observed that both the surface topography and chemistry as well as the microstructure are affected by the laser treatment. Single- and multiscale topographies were obtained by ns- and ps-DLIP, respectively. The nanosecond texturing led to an increased cubic β-phase fraction and the formation of a 25 nm thick passive layer, resulting in improved corrosion resistance. The ps-DLIP exhibited a defective surface oxide layer and a larger surface area due to the multi-scale topography, but nonetheless achieved improved corrosion resistance related to a partial wetting state.