Primary crystallization of an Al88Gd6Er 2Ni4 metallic glass

Abstract

Although pre-crystallization phase separation was reported in the Al 88Gd6Er2Ni4 amorphous alloy, this work has found no evidence for it. Surface crystallization was found to occur prior to the major crystallization of α-Al nanocrystals, which caused uneven foil thickness in transmission electron microscopy (TEM) specimens prepared by electro-polishing, resulting in artificial phase separation like contrast in TEM image. Partially crystallized samples were composed of α-Al nanocrystals with little solute content and an amorphous matrix. No solute enrichment was found at the interface between α-Al and the amorphous matrix, which acts as the heterogeneous nucleation sites for further formation of α-Al crystal, resulting in interconnected nanograin microstructure. © 2005 The Japan Institute of Metals.