Electrochemical Corrosion Behaviour Evaluation of Ti6Al4V-TiN Composite Materials Manufactured by DLD

Abstract

The electrochemical corrosion behaviour of Ti6Al4V metal matrix composites reinforced in situ with TiN ceramic phases was investigated. The composites were fabricated by Direct Laser Deposition (DLD) under a nitrogen atmosphere at two scanning speeds (5 and 10 mm/s), which promoted the formation of TiN during processing. Microstructural analysis using SEM and XRD confirmed a uniform distribution of TiN dendrites within the $$\alpha $$ – $$\beta $$ titanium matrix. Electrochemical testing in naturally aerated 3.5 wt% NaCl solution, including polarization resistance and cyclic polarization measurements, showed that adding TiN significantly enhanced uniform corrosion resistance. The Ti TiN v10 sample had the highest polarization resistance and the lowest corrosion rate, indicating better overall corrosion performance. However, cyclic polarization curves and surface analysis revealed a clear tendency toward pitting corrosion in these samples, linked to passive film breakdown. In contrast, Ti TiN v5 showed a reduced tendency toward localized corrosion, suggesting improved passivation stability under lower input conditions. These results emphasize the dual influence of TiN reinforcement and processing parameters on corrosion mechanisms, offering valuable insights for optimizing additive manufacturing strategies for titanium-based composites in saline environments. Graphical Abstract