Crystallization behavior and thermal stability of two-glassy phase Zr-based bulk metallic glasses

Based on the thermodynamic calculation, two phase separated Zr-based BMGs (Zr_63.8Ni_16.2Cu₁₅Al₅ and Zr ₆₆Cu_15.3Ni_8.7Al₁₀) which developed by the authors previous study were selected for investigating their crystallization behavior and thermal stabilities by means of differential scanning calorimetry (DSC), and X-ray diffractometry. The results show that the Zr₆₆Cu_15.3Ni_8.7Al₁₀ amorphous alloy exhibits higher GFA than the Zr_63.8Ni_16.2Cu ₁₅Al₅ amorphous alloy. But the Zr_63.8Ni _16.2Cu₁₅Al₅ amorphous alloy presents higher activation energy of crystallization (227 kJ/mole and 188 kJ/mole for Zr _63.8Ni_16.2Cu₁₅Al₅ and Zr ₆₆Cu_15.3Ni_8.7Al₁₀ BMGs, respectively). However, Zr₆₆Cu_15.3Ni_8.7Al ₁₀ amorphous alloy contains less atomic percentage of Cu and Ni elements (with positive heat of mixing) may result in forming less volume phase separation as well less interface area between these separated amorphous phase. Overall, the Zr₆₆Cu_15.3Ni_8.7Al₁₀ amorphous alloy exhibits longer incubation time at higher annealing temperature in comparison with the Zr_63.8Ni_16.2Cu₁₅Al ₅ amorphous alloy, suggesting that the amorphous alloy which contains fewer amounts of Cu and Ni elements would have better thermal stability.