This Laves phase intermetallic compound was studied, with regard to the nature of H-induced amorphization and the dynamic behavior of H atoms, by using X-ray diffraction, magnetic after-effect and thermal desorption spectrometry. It was found that the material could be amorphized by H-charging at temperatures which ranged from 523 to 593K; even at a H pressure of 0.1MPa. At lower temperatures, the material formed a crystalline hydride, whereas it decomposed into -Fe and DyH2 at higher temperatures. From the relaxation spectra which were obtained by using magnetic after-effect measurements, it was found that H atoms in the crystalline hydride occupied tetrahedral interstitial sites, which consisted of Fe3Dy and Fe2Dy2, with activation energies for short-range diffusion of 0.24 and 0.35eV, respectively. In the case of the amorphous hydride, the H atoms also occupied Dy3Fe sites with an activation energy of 0.43eV, and the distribution of activation energies became broader.

H.Atsumi, M.Hirscher, E.H.Büchler, J.Mössinger, H.Kronmüller: Journal of Alloys and Compounds, 1995, 231, 71-7