In Vitro Corrosion Behavior of Selective Laser Melted Ti-35Nb-7Zr-5Ta

Ti-35Nb-7Zr-5Ta (TNZT) alloy has been fabricated by selective laser melting (SLM) at different build orientations with respect to the base plate and the resulting disparities in the grain shape, size, preferred orientations and lattice strains have been determined. Potentiodynamic polarization tests performed under in vitro conditions indicated that the specimens built at 45 degrees orientation showed the highest polarization resistance (24.5 k omega cm(2)) and lowest rate of corrosion (0.23 mu A cm(-2)) compared to the specimens built at other orientations. The corrosion behaviors of the SLM specimens have been correlated with their microstructural features and further compared with that of its spark plasma sintered (SPS) counterpart and commercial alloys such as Ti6Al4V and Ti6Al7Nb. Electrochemical impedance spectroscopy and potentiostatic measurements have revealed that the passive film forming on the TNZT sample at 45 degrees orientation is highly stable and more protective than that of the other samples. Auger electron spectroscopy has confirmed that both Ti and Nb participate actively in the passive film formation on the SLM TNZT alloy.

Automated summary

The Ti-35Nb-7Zr-5Ta (TNZT) alloy fabricated by selective laser melting (SLM) shows varying corrosion behaviors based on different build orientations, with specimens built at 45 degrees orientation exhibiting the highest polarization resistance and lowest corrosion rate. The passive film formed on samples at 45 degrees orientation is more stable and protective compared to other orientations, involving active participation of both Ti and Nb in the film formation process.