Corrosion and passivation behavior of Ti-6Al-4V surfaces treated with high-energy pulsed laser: A comparative study of cast and 3D-printed specimens in a NaCl solution

This study explores using high-energy pulsed laser to improve the surface property and corrosion behavior of Ti-6Al-4V, aiming to develop a more eco-friendly and efficient approach. The study comprises conventional cast samples, advanced 3D-printed samples, and their respective laser-treated counterparts, all tested in a 3.5 wt% NaCl solution. The findings showed that sample 3 (as-3D-printed) had a more stable passivation film than sample 1 (as-cast). The laser-treated surface of sample 2 (laser-treated cast) greatly enhances film stability and resistance. Moreover, sample 4 (laser-treated 3D-printed) exhibited significantly better corrosion performance compared to sample 3 (as-3D-printed) due to the increased thickness of the passivation film in the laser-treated samples, resulting in higher film corrosion resistance. The results reveal that laser remelting treatment can eliminate macroscopic defects, reduce grain size, increase grain boundary density, and generate denser and more stable passivation films on the surface of Ti-6Al-4V, leading to reduced corrosion currents during dynamic potential polarization. Furthermore, laser remelting treatment has the capability to transform and refine the α phase into a finer lamellar and needle-like structure, thereby increasing the density of passivation nucleation sites during the corrosion process, resulting in the formation of a high-density passivation layer, and ultimately improving the corrosion resistance. By gaining a better understanding of the underlying mechanisms involved in high-energy pulsed treatment, this work provides valuable insights that can be used to optimize the treatment process and improve the overall surface properties of Ti-6Al-4V alloys. [Display omitted] •The microstructure of cast and 3D-printed Ti-6Al-4V differs, impacting passivation film thickness and resistance.•Laser remelting treatment significantly improves corrosion resistance of cast and 3D-printed parts.•Laser treatment increases the density of grain boundaries on surface, improving passivation layer stability.