The effect of Y addition on the crystallization behaviors of Zr-Cu-Ni-Al bulk metallic glasses

Crystallization behaviors of Zr_53.8Cu_29.1Ni_7.3Al_9.8 (Zr53) and Zr_53.8Cu_29.1Ni_7.3Al_9.8Y₁ (Zr52Y1) bulk metallic glasses (BMGs) were studied using differential scanning calorimetry (DSC), X-ray diffraction, high-resolution transmission electron microscopy (HRTEM) and high-angle annular dark field-scanning transmission electron microscopy (HADDF-STEM). The DSC curves had been analyzed using activation energy and kinetic models. The results revealed that the minor addition of yttrium leads to the increasing nucleation rate at the initial stage, the tardiness of crystal grain growth at the advanced stage and the transformation of main crystallized products from Cu₁₀Zr₇ to CuZr₂. The formation of a poorly-ordered precipitates were observed using the HRTEM and HADDF-STEM, which might be the precursor of Cu₁₀Zr₇ phases and result in the tardiness of initial nucleation on Zr53.