Impact of Microstructural and Surface Modifications on the Ti-45Nb Alloy’s Response to Bio-Environment

The Ti-45Nb (mass%) alloy’s corrosive and biocompatible response in simulated physiological conditions was investigated before and after its additional high-pressure torsion (HPT) and laser irradiation processing. The grain size reduction from 2.76 µm to ~ 200 nm and the appearance of laser-induced morphologically altered and highly oxidized surface led to the significant improvement of alloy corrosion resistance and cell–implant interaction. Moreover, an additional increase of the laser pulse energy from 5 to 15 mJ during the alloy irradiation in the air led to an increase in the surface oxygen content from 13.64 to 23.89% accompanied by an increase of excellent cell viability from 127.18 to 134.42%. As a result of the controlled alloy microstructural and surface modifications, the formation of protective bi-modal mixed Ti- and Nb-oxide external scale was enabled. The presence of this surface oxide scale enhanced the alloy’s resistance to corrosion deterioration and simultaneously boosted cell viability and proliferation.