Phases formed during crystallization of amorphous Al84Y9Ni5Co2 alloy

Understanding crystallization of amorphous metals is essential for the production of amorphous ribbons and powders and for the production of larger bodies by means of consolidation of an amorphous alloy powder. In this paper, we describe the evolution of the crystalline phases that form upon crystallization of amorphous Al84Y9Ni5Co2 ribbons during heating in a differential scanning calorimeter. X-ray diffraction and transmission electron microscopy (TEM) with energy dispersive spectroscopy were used to determine the phases formed. Crystallization occurs in three stages: (1) primary crystallization of α-Al, (2) formation of an unknown phase, and (3) formation of Al3Y, Al9Co2 and `Al16Ni3Y' needles.