Microstructure-dependent hydrogen embrittlement of stainless steels for green hydrogen applications

Abstract The storage and transportation of green hydrogen (GH 2 ) pose significant challenges for structural materials, particularly due to hydrogen embrittlement (HE), which can degrade the mechanical properties of steels through hydrogen–metal interactions. Understanding the susceptibility of candidate materials to hydrogen-induced damage is therefore essential for the safe deployment of hydrogen infrastructure. This study investigates the hydrogen embrittlement behavior of three stainless steels: ferritic stainless steel 410D, ferritic–martensitic stainless steel 410T, and duplex stainless steel 2205. Hydrogen was introduced through electrochemical charging via chronoamperometry in a 3.5 wt.% NaCl solution, a widely used laboratory approach to promote controlled hydrogen ingress and simulate hydrogen–material interactions relevant to hydrogen service conditions. The influence of charging temperature and exposure time was also evaluated. A comprehensive characterization methodology was employed, including microstructural analysis, chemical composition, hardness and microhardness measurements, uniaxial tensile tests before and after hydrogen exposure, and hydrogen permeation experiments to evaluate hydrogen absorption, diffusion, and transport behavior. The results indicate that hydrogen diffusivity plays a key role in the embrittlement response of the investigated alloys. The ferritic stainless steel 410D exhibited the highest susceptibility to hydrogen-induced degradation, showing the greatest reduction in mechanical properties and the highest hydrogen diffusion coefficient. In contrast, duplex stainless steel 2205 showed comparatively lower hydrogen diffusivity and reduced mechanical degradation under the tested conditions. Overall, the study highlights the critical influence of alloy microstructure, temperature, and exposure time on hydrogen embrittlement behavior and provides a comparative ranking of steel resistance to hydrogen-induced damage under the conditions analyzed.