Crystallization of Zr₅₀Cu₄₀Al₁₀ Metallic Glass by Rapid Heating Process

Abstract

The origin of thermal stability and crystallization process of Zr₅₀Cu₄₀Al₁₀ metallic glass have been investigated by means of differential scanning calorimetry (DSC), x-ray diffraction (XRD) and resonant ultrasound spectroscopy (RUS) techniques, by comparing to Zr₇₀Cu₂₀Al₁₀ and Zr₇₀Cu₃₀ glassy alloys. The thermal stability of Zr₅₀Cu₄₀Al₁₀ is significantly higher than those of the others. The x-ray diffraction analysis indicates that constituent atoms in Zr₅₀Cu₄₀Al₁₀ are closely packed in a glassy state. It was found from DSC that Zr₅₀Cu₄₀Al₁₀ glass shows a complicated crystallization process when it is heated at usual heating rates, but when it is rapidly heated, the ordered B2-type ZrCu (equilibrium phase higher than 984K) is formed as a primary phase. This behavior is discussed in terms of the long-range-diffusion of atoms.