Hydrogen Embrittlement mitigation through Layered diffusion patterns in Metals

Hydrogen embrittlement (HE) of metallic materials is one of the main challenges for the adoption of green H2 as a clean fuel.

Degradation of pipelines and vessels is nowadays avoided by conservative design and material selection, but novel mitigation strategies for hydrogen embrittlement will foster cost-effective technologies.I envisage an Additive Manufacturing strategy to tune hydrogen diffusion as an effective and novel method to mitigate or even supress HE.

The success of this framework requires the reconsideration of modelling and experimental techniques to characterise hydrogen transport and embrittlement in metals.

My background on computational mechanics, hydrogen diffusion simulation and Laser Powder Bed Fusion (LPBF) will guide the approach whereas the methodology will be enriched by innovative phase tailoring strategies and advanced computational and optimisation procedures.

Tailoring hydrogen diffusion in steels will be accomplished by exploiting the enormous difference in diffusivity between fcc and bcc iron phases.

Duplex Stainless Steels (DSS) that combine austenite (fcc) and ferrite (bcc) phases are thus considered as a first option to tune diffusion paths.

Additionally, localized nitrogen evaporation to directly control fcc or bcc formation during micro-LPBF of High Nitrogen Steels (HNS) will be achieved by local variation of laser parameters. The main goal is to protect critical regions and therefore to supress hydrogen-assisted cracking.

To produce shielding effects around stress concentrators, bcc/fcc helmets will be optimised by coupled modelling frameworks including hydrogen transport and fracture.

Trapping and multiphase diffusion will be assessed by novel modelling procedures from thermal desorption and permeation experimental results.

Finally, the effectiveness of the optimised tailored helmets will be evaluated by in-situ testing in gaseous H2, paving the way for resistant components to transport and store high-pressure hydrogen.