Fig. 1 Illustration of experimental procedures: a1-a3 schematic of hydrogen adsorption and desorption processes, b electrochemical hydrogen charging set-up, c thermal desorption rate curves showing the diffusible hydrogen contents for samples under different conditions, d BSD and EBSD overviews of the deformation region of interest. BSD: backscattered diffraction. EBSD: electron backscattered diffraction

Fig. 2 ECC images displaying the dislocation configurations: a un-charged sample and b hydrogen-charged before deformation; c un-charged sample and d hydrogen-charged sample at a global strain amplitude of 2%. An example showing the estimation process of dislocation density from ECC images is displayed in a. The intersections of individual dislocations with the surface are marked by red dots. Dislocations density is obtained by counting the total number of the red dots divided by the area of blue rectangle. Inset in c showing the simulated electron channeling pattern. TD: tensile direction

Fig. 3 Evolution of stacking fault configurations in the deformed sample a1 before and a2 after vacuum aging (hydrogen desorption)

Fig. 4 Evolution of the dislocation configurations in the deformed sample a1, b1 before vacuum aging and a2, b2 after vacuum aging (hydrogen desorption). Enlarged views of interested regions in b1, b2 displayed in rectangles with corresponding colors. a3 An example showing a typical pile-up feature in the hydrogen-free sample. GB: grain boundary

Fig. 5 Schematic illustration of the hydrogen-dislocation interaction mechanisms after a hydrogen adsorption and b hydrogen desorption