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.

Hydrogen Diffusion in DyFe2 and its Effect on Magnetic Properties. H.Atsumi, M.Hirscher, E.H.Büchler, J.Mössinger, H.Kronmüller: Journal of Alloys and Compounds, 1995, 231, 71-7

Table 69

Diffusion of H in Deformed A508 Steel