In-situ electron diffraction study of bulk amorphous La55Al25Ni20 in the supercooled liquid region

A change of atomic structure of amorphous La55Ni25Al20 alloy in the course of annealing in the "supercooled liquid region" has been investigated by in-situ electron diffraction and high-resolution electron microscopy (HREM) using a specimen heating-stage in TEM. For recording electron intensities an imaging plate was used. In order to remove the inelastically scattered electrons an energy filter was used for recording electron diffraction patterns. No appreciable change was found in the in-situ HREM observation across the glass transition temperature on heating. However, atomic pair distribution function (PDF) analysis revealed a clear structural change in the "supercooled liquid region". The observed structural change is concerned with the local development of strong atomic correlations especially for La-La and Al-Ni and also with the increase of structural volume. The atomic configurational change is closely related to the phase separation in the later crystallization stage.