Heat treatment of amorphous Al85Y5Ni10 and Al85Y10Ni5 alloys

Microstructural changes during annealing of amorphous Al85Y5Ni10 and Al85Y10Ni5 alloy ribbons have been studied by a combination of differential scanning calorimetry, transmission electron microscopy and X-ray diffractometry. As-solidified melt spun Al85Y5Ni10 consists of some atomic clusters or microcrystals embedded in an amorphous matrix, resulting in a shoulder on the amorphous halo diffraction pattern. The alloy crystallizes by primary crystallization of an fcc α solid solution followed by precipitation of orthorhombic Al3Ni. As solidified melt spun Al85Y10Ni5 consists of a fully amorphous structure with no shoulder on the amorphous halo diffraction pattern. The alloy crystallizes by primary crystallization of an fcc α solid solution followed by an eutectic reaction to form α and hexagonal A13Y.