Corrosion Behavior of Additively Manufactured Inconel Alloys

Additive manufacturing of Inconel alloys has unlocked unprecedented design freedom for critical components in aerospace, power generation and chemical processing. Yet the layer‐wise build processes introduce unique microstructural features—such as fine cellular dendrites, residual porosity and elemental segregation—that can compromise native corrosion resistance. In particular, rapid solidification and repeated thermal cycling foster high densities of grain boundaries and microsegregation of elements like niobium and chromium, which alter passive‐film formation and oxide scale adherence. Surface roughness intrinsic to powder‐bed fusion methods further exacerbates localised attack by creating sites for chloride entrapment and pitting nucleation. Post‐processing routes—including tailored heat treatments, hot isostatic pressing and mechanical finishing—can coarsen grains, close internal voids and smooth external surfaces, thereby re-establishing robust protective films. Recent advances have elucidated the interplay between alloy chemistry, build orientation and post-build treatment in determining intergranular oxidation, high-temperature corrosion kinetics and pitting susceptibility. A comprehensive understanding of these phenomena is essential to certify additively manufactured Inconel parts for aggressive service environments and to optimise processing protocols that safeguard long-term performance.

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Corrosion Behavior of Additively Manufactured Inconel Alloys publication trend

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

Technical terms

Additive Manufacturing: Layer-by-layer fabrication of components from metal powder or wire feedstock.

Inconel Alloys: Family of nickel-based superalloys valued for high-temperature strength and corrosion resistance.

Intergranular Oxidation: Preferential oxide formation along grain boundaries that undermines cohesion.

Passive Film: Thin, protective oxide layer that retards further metal dissolution.

Grain Boundary: Interface between adjacent crystalline grains with distinct orientations.

Hot Isostatic Pressing: High-pressure, high-temperature treatment to densify and reduce internal porosity.

Shot Peening: Mechanical surface treatment inducing compressive residual stress to improve fatigue and corrosion resistance.

Surface Roughness: Quantitative measure of texture height variations that influences film formation and pit initiation.

References

1. Intergranular oxidation of additively manufactured Ni-base alloy 625: The role of Si. Corrosion Science (2023).
2. High-temperature oxidation behavior of additively manufactured IN625: Effect of microstructure and grain size. Corrosion Science (2022).
3. Chemical and mechanical post-processing of Alloy 718 built via electron beam-powder bed fusion: Surface texture and corrosion behavior. Materials & Design (2022).