Comparison of Crystallization Process of Amorphous Zr₂Ni Alloy and Metallic Zr₂Cu Glass

Abstract

Crystal nucleation and time evolution during isothermal annealing in amorphous Zr₂Ni at several temperatures just below a crystallization temperature T_x and in supercooled liquid of metallic glass Zr₂Cu are examined using a technique of differential thermal analysis. Time dependence of the fraction of crystallization at several temperatures is analyzed by the Johnson-Mehl-Avrami equation. The Avrami exponent is 3.0±0.2 for Zr₂Ni and varies from about 3 to 7 for Zr₂Cu with increasing temperature. It is suggested for Zr₂Ni that the crystal growth at temperatures just below T_x is ruled by a short range diffusion process of constituent elements. The time evolution of crystallized fraction was not well scaled by the half of complete time for full crystallization.