An isotropic glass phase in Al-Fe-Si formed by a first order transition

Abstract

ABSTRACTWe present evidence of the nucleation and growth of a metallic glass phase from the melt, as if by a first-order transition. Microstructures of a number of rapidly solidified Al-Fe-Si alloys demonstrate that this glassy phase, which we term q-glass, is not a kinetically frozen liquid. It is the first phase to form from the melt as isolated nuclei that grow and deplete the melt of iron and silicon. From the nucleation behavior and the compositional partitioning, we infer an interface between the q-glass and the melt, and that, in a narrow composition range, the q-glass has a lower energy and entropy (is more ordered) than a conventional glass.