Crystallization of amorphous Zr60Al15Ni25 alloy

The phase formation and crystallization kinetics during the thermal treatment of amorphous Zr₆₀Al₁₅Ni₂₅ alloy were investigated by differential scanning calorimetry (DSC) and X-ray diffraction (XRD). By lowering the isothermal annealing temperatures, it is revealed that the crystallization of the amorphous Zr₆₀Al₁₅Ni₂₅ alloy consists of a primary transformation followed by a polymorphic transformation, corresponding to the precipitations of hexagonal Zr₆Al₂Ni and the Zr₅AlNi₄ with a U₃Si₂-typed superstructure. The primary phase being Zr₆Al₂Ni rather than Zr₅AlNi₄ in the crystallization is because the latter has a complex structure and its formation requires the diffusion of Al and Zr atoms on a large scale.