Low-Temperature Deformation Mechanisms in Ultrafine-Grained Stainless Steel: Operando Neutron Diffraction

Hydrogen is attracting considerable attention as a clean energy carrier for a sustainable society. Efficient hydrogen transportation and storage often require liquid hydrogen, necessitating structural materials with excellent cryogenic performance.

FCC stainless steels are promising candidates because of their high resistance to hydrogen embrittlement; however, their yield strength at low temperatures remains insufficient. Grain refinement into the ultrafine-grained regime is an effective approach to improve the strength of metastable austenitic stainless steels, although their low-temperature deformation behavior is still not fully understood.

In this study, operando neutron diffraction combined with digital image correlation was employed to investigate the deformation mechanisms of ultrafine-grained metastable austenitic stainless steel under cryogenic conditions. Detailed results and the associated strengthening mechanisms will be presented.