Local structure of binary alloys Zr70Pd30

The rearrangements of the local environment of zirconium and palladium atoms in the binary alloy Zr70Pd30 upon the transformation from the crystalline to the quasicrystalline and amorphous states were studied by extended X-ray absorption fine structure (EXAFS) analysis. In the quasicrystalline phase, the icosahedral environment was found to be formed only around the zirconium ions because of shifts of both the palladium and zirconium atoms to the center of the cluster; in addition, the structure of the icosahedral clusters is distorted. The transformation from the crystalline to the quasicrystalline phase is accompanied by the atomic rearrangement in the immediate environment of palladium, thus resulting in the partial displacement of palladium by zirconium. In the amorphous phase, the icosahedral short-range order is not observed. A model for the description of the structure of the quasicrystalline phase of Zr70Pd30 is proposed.