Effects of hydrogen and deuterium concentration on measurements on the solubility and diffusivity of hydrogen isotopes in yttrium

Abstract

The solubility and diffusivity of hydrogen and deuterium in polycrystalline α-yttrium have been measured in the temperature range 1073–1273 K and at hydrogen and deuterium concentrations, θ(H : Y and D : Y, atomic ratio), of 0–0.4. The measured solubility obeys the relationship p=k[θ/(1 –θ)]², where p is the hydrogen pressure and k is a constant independent of θ. The measured diffusion coefficients for hydrogen and deuterium increased with θ. The experimental result has been explained by a model in which a hydrogen atom can occupy a pair of two nearest-neighbour tetrahedral sites of the hcp α-yttrium lattice and move almost freely between the two sites.