Local structure and site substitution in amorphous and quasicrystalline Zr-Ti-Ni-(Cu) alloys

Local structures of amorphous and quasicrystalline phases in Zr-Ti-Ni and Zr-Ti-Ni-Cu alloys have been studied by means of x-ray absorption spectroscopy. The amorphous phases show a high degree of icosahedral short-range order. In all investigated systems local order around Cu and Ni atoms was found to be nearly identical pointing to site substitution of Ni by Cu as the reason for an improved glass forming ability when Ni is partly substituted by Cu. The results strengthen an icosahedral cluster based approach for the structure of metallic glasses and indicate the importance of the medium-range order on glass formation. (C) 2010 American Institute of Physics. [doi:10.1063/1.3467265