Slow diffusion of hydrogen at a screw dislocation core in α-iron

Here we demonstrate and characterize the H-diffusion behavior around a screw dislocation in body-centered cubic (bcc) alpha-Fe by performing path-integral molecular dynamics modeling and adopting an ab initio-based potential. Counterintuitively, our results indicate that the H diffusivity along the dislocation line is significantly lower than lattice diffusion. Thus, the "fast" pipe diffusion does not occur for H in alpha-Fe.