On the formation of a phase with tenfold symmetry in amorphous Ni–Zr alloys

Abstract

The splat-quenched Ni₅₀Zr₅₀ alloy has a rosette-shaped phase with tenfold symmetry. The structure of this phase has been interpreted (Yang, 1985) as “tenfold twins” of the orthorhombic NiZr phase. The formation and the feature of the phase with tenfold symmetry have been investigated in Ni₅₀Zr₅₀, Ni_50−xCu_xZr₅₀ and Ni_50−xCo_xZr₅₀ amorphous alloys. It was found that this phase forms first during the crystallization process. The structure comes nearer to the structure of a quasi-crystal through the influence of Cu and Co atoms.

Key Words:

• Quasi-crystal
• icosahedral phase
• tenfold symmetry
• Ni(Cu, Co)–Zr amorphous metal