Influence of mechanically activated hydrogen diffusivity on the toughness of metallic materials for the storage and transport of hydrogen under pressure

The transition to a zero-carbon economy based on hydrogen presents significant challenges, particularly with respect to hydrogen storage and transport under high pressure. A major concern is the hydrogen embrittlement associated to the degradation of the mechanical properties of metals. This issue is exacerbated at high pressure which drives hydrogen deeper into the metal, referred to as mechanically activated hydrogen diffusivity. In this context, it is critical to develop new alloys or multilayer solutions with either zero or significantly reduced hydrogen permeability, low sensitivity to hydrogen embrittlement, and mechanical properties that meet the specifications required for hydrogen storage and transport applications. As a first step, metals were selected based on their ability to meet these key constraints, following the Ashby materials selection approach in order to guide the development of a multilayer. To simulate the actual hydrogen transport and storage conditions, an experimental setup has been designed to study hydrogen permeation in the presence of a pressure differential between the surfaces of the tested samples. The materials are tested in cryogenic conditions to assess their mechanical properties at low temperatures.