Phases formed during crystallization of amorphous Al84Y9Ni5Co2 alloy

Understanding crystallization of amorphous metals is essential for the prod uction of amorphous ribbons and powders and for the production of larger bo dies by means of consolidation of an amorphous alloy powder. In this paper, we describe the evolution of the crystalline phases that form upon crystal lization of amorphous Al84Y9Ni5Co2 ribbons during heating in a differential scanning calorimeter. X-ray diffraction and transmission electron microsco py (TEM) with energy dispersive spectroscopy were used to determine the pha ses formed. Crystallization occurs in three stages: (1) primary crystalliza tion of alpha-Al, (2) formation of an unknown phase, and (3) formation of A l3Y, Al9Co2 and 'Al16Ni3Y' needles. (C) 2000 Published by Elsevier Science B.V. All rights reserved.