High electrochemical corrosion properties of TA10 alloy fabricated through selective laser melting

Additive manufacturing technology has a good application prospect in marine titanium (Ti) alloy manufacturing. In this study, Ti-0.3Mo-0.8Ni (TA10) alloy samples were fabricated via selective laser melting (SLM). Electrochemical corrosion mechanism and influences of microstructure were investigated. The SLM process significantly refines microstructure of TA10 alloy, and the finer basket α phase structure increases density of grain boundaries, which stabilizes passive film. Among them, the larger the polarization resistance R p value that was calculated based on electrochemical test results, the better the electrochemical corrosion resistance. R p value of TA10 manufactured by SLM is 619.9 Ω cm 2 , which is higher than that of as-cast TA10 (459.4 Ω cm 2 ). At the same time, SLM-prepared samples have a more uniform structure, which reduces the tendency of galvanic corrosion. Electrochemical analysis reveals that SLM-prepared sample forms a porous passive film structure in 5 mol/L HCl solution. Static immersion tests and X-ray photoelectron spectroscopy results indicate that SLM-prepared samples have more stable passive films, and post-SLM annealing treatment further increases oxide content in passive films. Total mass loss of SLM-prepared samples is 34.83±0.8 mg cm −2 , which is significantly lower than the total mass loss of as-cast TA10 samples (45.28±0.4 mg cm −2 ) in static immersion tests.