Impact of Hydrogen Incorporation on Electronic and Magnetic Structure of X2CrNi18‐9 Stainless Steel

Hydrogen absorption significantly alters the mechanical properties of steel. It simultaneously influences the electronic and magneto‐structural properties, helping to interpret how hydrogen is incorporated. This study investigates the influence of hydrogen incorporation on the electronic and magneto‐structural properties of X2CrNi18‐9 stainless steel in different microstructural states. Microstructural characterization included analytic electron microscopy mapping, X‐ray diffraction, and thermodynamic stability maps to evaluate grain size, dislocation density, and chemical homogeneity. Electronic properties were characterized using the Seebeck coefficient, while the magneto‐structural properties were investigated using diffuse neutron scattering and small‐angle neutron scattering (SANS). Hydrogen incorporation produced clear changes in the Seebeck coefficients. Magnetic SANS combined with diffuse neutron scattering revealed nanoscale inhomogeneities with the same fcc structure as the bulk, but with correlation lengths of only a few nanometers. The size of these inhomogeneities increased with hydrogen incorporation, suggesting that hydrogen preferentially accumulates in their vicinity. These results indicate that nanoscale inhomogeneities play a significant role in hydrogen incorporation, whereas no direct correlation was observed between the electronic and magneto‐structural properties and the dislocation density. We anticipate that such studies will support, in the medium term, the development of design guidelines for improving the hydrogen resistance of steels.