On the atomic structure of Zr–Ni and Zr–Ni–Al metallic glasses

Abstract

Using real space pair distribution functions derived from high precision x-ray diffraction data, the local atomic structure of Zr–Ni and Zr–Ni–Al metallic glasses was investigated. Unlike Zr–Cu metallic glasses, the structure of Zr–Ni metallic glasses cannot be approached with an ideal solution model, due to strong attractive interactions between Zr and Ni atoms, which promote chemical short range order. Addition of Al can be beneficial for the glass forming ability of Zr–Ni metallic glasses. The atomic size of Al, being intermediate to those of Zr and Ni and the strongly attractive interactions between Zr–Al and Zr–Ni atoms can lead to highly negative volumes of mixing ΔVmix, and to denser atomic structures, reduced atomic mobility in the liquid and easier suppression of crystallization in the undercooled liquid state