Direct measurement of hydrogen dislocation pipe diffusion in deformed polycrystalline Pd using quasielastic neutron scattering.

The temperature-dependent diffusivity D(T) of hydrogen solute atoms trapped at dislocations-dislocation pipe diffusion of hydrogen-in deformed polycrystalline PdH(x) (x∼10(-3)  [H]/[Pd]) has been quantified with quasielastic neutron scattering between 150 and 400 K. We observe diffusion coefficients for trapped hydrogen elevated by one to two orders of magnitude above bulk diffusion. Arrhenius diffusion behavior has been observed for dislocation pipe diffusion and regular bulk diffusion, the latter in well-annealed polycrystalline Pd.