Devitrification behavior around supercooled liquid region of an Al85Ni5Y8Co2 metallic glass

Melt-spun and annealed Al85Ni5Y8Co2 metallic glass, with a large supercooled liquid region, were investigated by means of differential scanning calorimetry (DSC), transmission electron microscopy (TEM), and small-angle x-ray scattering (SAXS). TEM studies revealed that the as-quenched ribbons were fully amorphous. Further, the SAXS measurements showed that no evidence for compositional inhomogeneities associated with amorphous phase separation was found in the as-quenched state and the early stage annealing prior to devitrification. The primary crystallization of this glass was characterized, intriguingly, which appeared to be proceeded with an initial thermal relaxation, then alpha-Al nanocrystal nucleation with a limited number, finally a high density of nanocrystals nucleation and growth.