Electron diffraction study of a noncrystalline Zr?Ni phase

Metastable noncrystalline phases were retained by rapid quenching Zr?Ni alloys from the liquid state over the composition range 25 to 70 at. pct Ni. The X-ray and electron diffraction patterns of the metastable phases showed broad diffraction maxima indicating absence of long range crystalline order in them. The pair function of the metastable noncrystalline phase in a splat cooled Zr_0.7Ni_0.3 alloy was determined from the electron diffraction data. The various interatomic distances corresponding to the positions of the peaks in the pair function curve were determined. The nearest-neighbors coordination number was computed from the area under the first peak. The radius of the first near neighbor shell is 2.95 Å and the ratio of the second to the first interatomic distance is equal to 1.41 which is significantly lower than that observed in most metallic liquids. The local atomic arrangement in the non-crystalline Zr_0.7Ni_0.3 alloy was shown to be based on simple fcc coordination.