Corrosion Resistance of Additively Manufactured Titanium Alloys

Additive manufacturing of titanium alloys, particularly Ti-6Al-4V, has revolutionised the fabrication of lightweight, high-performance components for aerospace, biomedical and marine applications. Layer-by-layer processes such as laser powder bed fusion and electron beam melting produce unique microstructures—often characterised by acicular martensitic α′ phases, refined grain boundaries and varying porosity—that differ markedly from those of wrought or cast counterparts. These microstructural features exert a profound influence on passive film formation, repassivation kinetics and susceptibility to localized attack in chloride-containing environments. Surface roughness, defect density and residual stress further modulate electrochemical behaviour by altering film stability and promoting microgalvanic cells. Recent advances have focused on in-situ and post-process strategies—such as surface remelting, laser texturing and heat treatments—to tailor phase distribution, reduce defect populations and enhance repassivation rates. Together, these efforts aim to establish robust processing–structure–property relationships, ensuring that additively manufactured titanium components meet stringent corrosion-resistance requirements for long-term service in demanding environments.

Research from Nature Portfolio

Recent studies have demonstrated that surface re-finishing by electron beam surface remelting markedly enhances corrosion resistance of as-built electron beam melted Ti-6Al-4V. By reducing surface roughness by over 80 %, the remelting treatment lowers the anodic dissolution rate in chloride media. Electrochemical tests in sodium chloride solution reveal that remelted surfaces exhibit corrosion current densities up to five times lower than untreated counterparts, reflecting improved passive film adherence. Importantly, these improvements arise primarily from geometric smoothing rather than changes in bulk microstructure, indicating that targeted surface engineering can serve as an effective in-situ finishing technique without compromising underlying metallurgical attributes.

Corrosion Resistance of Additively Manufactured Titanium Alloys publication trend

The graph below shows the total number of articles in corrosion resistance of additively manufactured titanium alloys across all publications each year (not limited to Nature Index journals).

Technical terms

Additive Manufacturing (AM): A suite of layer-wise fabrication techniques that build components directly from digital models, enabling complex geometries and customisation.

Laser Powder Bed Fusion (LPBF): An AM process in which a laser selectively fuses metal powder particles to form successive layers, often yielding acicular martensitic microstructures.

Electron Beam Melting (EBM): A high-energy AM technique using an electron beam in vacuum to melt metal powder, typically producing coarser β phase distributions and higher interlayer bonding.

Passive Film: A thin, protective oxide layer (primarily TiO₂) that forms spontaneously on titanium surfaces and retards further corrosion by acting as a barrier.

Repassivation: The rapid re-formation of a stable passive film over a damaged or dissolved region, critical for resisting localized corrosion and pitting.

References

1. Cavitation erosion-corrosion properties of as-cast TC4 and LPBF TC4 in 0.6 mol/L NaCl solution: A comparison investigation. Ultrasonics Sonochemistry (2024).
2. Electron beam surface remelting enhanced corrosion resistance of additively manufactured Ti-6Al-4V as a potential in-situ re-finishing technique. Scientific Reports (2022).
3. Corrosion and passivation behavior of laser powder bed fusion produced Ti-6Al-4V under various prior plastic deformation strains. Corrosion Science (2024).
4. Comparative Study on Passive Film Formation Mechanism of Cast and PBF-LB/M-TC4 in Simulated Physiological Solution. Materials (2024).