New model for the diffusion behavior of hydrogen in metallic glasses

Both experimental and simulation results have indicated the deviation from Arrhenius law of the diffusion coefficient of hydrogen in metallic glasses. This deviation was traditionally explained by the existence of various kinds of jumps or in terms of continuous distributions of activation energies due to different kinds of disorder. A new model is suggested, which relates this deviation to the temperature dependence of the short-range order (SRO). The suggested model is applied to simulate the diffusion behavior of hydrogen in dilute amorphous Fe-H, Fe-Si-H and Fe-B-H alloys. The effect of the alloying elements on the activation energy of hydrogen diffusion in amorphous iron is discussed in terms of their electronic structure and mean volume.