Hydrogen charging and desorption from microstructural viewpoint: A method for deconvoluting hydrogen desorption spectra and unveiling the hydrogen-microstructure interaction

Understanding the interaction of hydrogen with microstructure features in metallic materials is crucial for designing hydrogen-resistant alloys. Although thermal desorption spectroscopy (TDS) is widely used for investigating the hydrogen binding behavior of various microstructural features, its application to low hydrogen diffusivity face-centered cubic (fcc) materials is limited. This study establishes a method to investigate deuterium (hydrogen isotope) adsorption, diffusion, and desorption using a microscale hydrogen transport model, directly reconstructed from electron backscatter diffraction (EBSD) maps. Austenitic steel SS316L, known for its high hydrogen solubility, low diffusivity, and strong resistance to embrittlement, is selected as a demonstration material. The model is validated against experimentally obtained TDS measurements in both, as-heat-treated and pre-strained conditions. Key insights into the interaction of hydrogen with dislocations and grain boundaries as revealed in this work are difficult to obtain from experiments alone and are expected to facilitate design of alloys for hydrogen infrastructure.