Laser directed energy deposited, ultrafine-grained functional titanium-copper alloys tailored for marine environments: Antibacterial and anti-microbial corrosion studies

The microorganism-rich nature of the ocean imposes great challenges to the structural integrity of metals over their service lifespan, including titanium (Ti) alloys, which are usually prone to microbiologically influenced corrosion (MIC). So, multifunctional anti-MIC Ti alloys need to be developed and studied. This paper investigates the effect of copper (Cu) concentration on the MIC resistance of a series of additively manufactured, ultrafine-grained Ti- x Cu ( x = 3.5, 6.5 and 8.5 in wt.%) alloys. The dependence of the corrosion resistance and MIC resistance on the Cu concentration of Ti-Cu alloy is interpreted considering all conceivable mechanisms. The mechanisms for excellent corrosion resistance of Ti-Cu alloy in seawater are attributed to the strong passive film and small surface potential difference between phases. Microstructural characterization reveals that uniformly distributed, nanosized Ti 2 Cu phase led to increased reactive oxygen species in the bacterial membrane, which is the root reason for the superb anti-bacterial property (99.2%) for Ti-8.5Cu. Compared to pure Ti and Ti-6Al-4V, Ti-8.5Cu alloy features both high strength (yield stress > 10 0 0 MPa) and the best MIC resistance (97.5%). The combination of such balanced properties enables this functional 3D printed Ti-Cu alloy to become an ideal material for load-bearing applications in the marine environment.& COPY; 2023 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology. This is an open access article under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ )

Automated summary

This paper investigates the effect of copper concentration on the microbiologically influenced corrosion (MIC) resistance of additively manufactured, ultrafine-grained Ti-Cu alloys. The results show that Ti-8.5Cu alloy exhibits the best corrosion resistance and MIC resistance due to its strong passive film and small surface potential difference between phases. The alloy has high strength and excellent antimicrobial properties, making it ideal for load-bearing applications in the marine environment.