Crystallization behavior and structural stability of Zr₅₀Cu ₄₀Al₁₀ bulk metallic glass

We have investigated the origin of significantly high thermal stability of Zr₅₀Cu₄₀Al₁₀ metallic glass and its crystallization behavior as compared to Zr₇₀Cu₂₀Al ₁₀ and Zr₇₀Cu₃₀ glassy alloys, by differential scanning calorimetry (DSC), x-ray diffraction (XRD) and resonant ultrasound spectroscopy (RUS) techniques. It was found from XRD and DSC analyses that (i) constituent atoms in Zr₅₀Cu₄₀Al₁₀ are highly close-packed in a glassy state and (ii) Zr₅₀Cu₄₀Al ₁₀ glass shows a complicated crystallization process when it is heated at conventional heating rates, but when it is rapidly heated, the ordered B2-type ZrCu is dominantly formed. The high thermal stability and its crystallization behavior are discussed in terms of the long-range-diffusion of atoms and elastic strain energy.