New approaches to understanding hydrogen embrittlement in steels

The aim of the first project is to develop a fundamental understanding of hydrogen embrittlement in steels, using a variety of characterisation techniques including cryogenic Focussed Ion Beam (FIB) and Atom Probe Tomography (APT). The anticipated major expansion in hydrogen production, transportation and utilisation calls for massive investments in

infrastructure. One of the biggest challenges of the hydrogen economy is storage and transport. Current hydrogen storage

technology involves either physical storage systems such as pressurised canisters (typically made from steel, which may be

embrittled by the cryogenic temperatures and hydrogen exposures- or the synergistic effects of both) or materials such as

hydrides which can store hydrogen in a reacted form, that will then need to be extracted. Hydrogen embrittlement in steel at

cryogenic temperatures is poorly understood - and the lack of mechanistic insights means that material selection or bespoke

alloy development remains challenging. Steels that are resistant to embrittlement at room temperature are certainly available

but tend to be expensive, and their behaviour under cryogenic temperatures has not been well-explored. Improved fundamental

understanding of the processes of hydrogen dissolution in the metal, and the role of microstructural features that act as

hydrogen trap sites, will assist in screening steels for hydrogen service. This iCASE project will therefore focus on the

experimental investigation of hydrogen dissolution, diffusion and distribution in different steels - with the steels studied and

characterized under cryo-conditions. Using new experimental facilities at Imperial, we have a chance to create a step-change in understanding the properties.