An anomalous X-ray structural study of an amorphous La 55Al 25Ni 20 alloy with a wide supercooled liquid region

Abstract

The atomic structures of amorphous La 55Al 25Ni 20 alloys which have a wide supercooled liquid region and a high reduced glass transition temperature have been studied using anomalous X-ray scattering (AXS) at the Ni K-absorption edge as well as the ordinary X-ray diffraction with Mo Kα radiation. The interference functions and the radial distribution functions were determined for the amorphous alloys as-quenched and after annealing at various temperatures and also for a fully crystallized sample. These systematic structural studies revealed a drastic change in Ni environment upon crystallization. The need for such atomic rearrangements around the Ni atoms during crystallization may be the reason why the amorphous phase is thermally stable.