Precipitation of icosahedral quasicrystalline phase in Zr-Cu-Rh metallic glasses: dependence of particle size on Rh concentration

¹ Inoue Superliquid Glass Project, ERATO, JST, Sendai 982-0807, Japan
² Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan

Corresponding author: chl2@lehigh.edu

Received: 3 January 2002
Revised: 5 March 2002
Accepted: 7 March 2002
Published online: 15 May 2002

Abstract

The crystallization processes of Zr₇₀Cu₂₀Rh₁₀ and Zr₇₀Cu_27.5Rh_2.5 metallic glasses were studied. The initial precipitates are the mixture of an icosahedral quasicrystalline phase (I phase) and a face centered cubic Zr₂Rh phase (fcc-Zr₂Rh) for Zr₇₀Cu₂₀Rh₁₀ alloy and that for the Zr₇₀Cu_27.5Rh_2.5 alloy is a single I phase. Under optimum annealing conditions, the largest I phase particle size is 40 nm and 80 nm for Zr₇₀Cu₂₀Rh₁₀ and Zr₇₀Cu_27.5Rh_2.5, respectively. To explain these results, it is assumed that icosahedral atomic cluster exists in the metallic glasses, which serves as the seeds for the precipitation of metastable I and FCC-Zr₂Rh phases. Further, it is suggested that the number density of icosahedral atomic cluster and the ease of fcc-Zr₂Rh phase formation depend on the Rh concentration, which explain the above-mentioned dependence of the I phase particle size on Rh concentration.