Extended X-ray absorption fine-structure study of the hydrogen location in a Ti-Zr-Ni icosahedral quasicrystal and a 1/1 bcc crystal approximant

Extended X-ray absorption fine-structure measurements have been performed on Ti- Zr-Ni alloys using the Dispositif de Collision dans l’lgloo synchrotron radiation facility. Both a multigrained icosahedral quasicrystal and a 1/1 bcc polycrystalline approximant were studied. Alloys hydrogenated to a hydrogen-to-metal ratio of 1.7 for the icosahedral phase and 1.4 for the crystalline phase were also studied. The local atomic structures, which are different around the different types of atom, titanium, zirconium and nickel, are very similar in the non-hydrogenated alloys, crystal or quasicrystal. Drastic changes are observed in the local order in both hydrogenated alloys with modifications of distances and an increase in the disorder. Moreover, these modifications are slightly different in the 1/1 and icosahedral alloys after hydrogenation.