Abstract:

Cold spray additive manufacturing has gained increasing attention as a viable method for repairing titanium (Ti) components operating in aggressive environments. Despite its growing use, the electrochemical behavior of cold-sprayed commercially pure (CP)-Ti under the combined influence of acidic and chloride-containing media remains insufficiently understood. In this study, the corrosion and mechanical performance of additively manufactured angular Ti produced by cold spray were evaluated. Crevice corrosion testing was performed according to ASTM G48-11, while electrochemical behavior was characterized using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) in 60 g/L sulfuric acid (H₂SO₄), 20 g/L sodium chloride (NaCl), and mixed solutions. The crevice corrosion results demonstrated that the additively manufactured CP-Ti was not susceptible to crevice corrosion under the tested conditions. Polarization curves and EIS spectra, however, revealed notable differences between the additively manufactured material and the bulk rolled plate. A synergistic effect between acidic and chloride environments was observed. The additively manufactured Ti exhibited lower charge-transfer resistance compared with that of the bulk-rolled Ti plate in 20g/L NaCl and mixed solution. This behavior is attributed to microstructural heterogeneities, including splat boundaries and interparticle interfaces. The micro and nanomechanical properties of the additively manufactured Ti were investigated using Vickers microindentation and Berkovich nanoindentation. These findings are consistent with the presence of heterogeneous deformation zones governed by splat morphology, bonding quality, and grain refinement induced by high-strain-rate impacts during deposition. Overall, this work provides new insights into the relationship between microstructural features, electrochemical response, and indentation-based mechanical behavior in additively manufactured CP-Ti.

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Ms. Yu Gao