On calorimetric study of the fragility in bulk metallic glasses with low glass transition temperature: (Ce_(0.72)Cu_(0.28))_(90-x)Al_(10)Fe_x (x = 0, 5 or 10) and Zn_(38)Mg_(12)Ca_(32)Yb_(18)

摘要

Compared with conventional bulk metallic glasses, Ce-based and Zn-based bulk metallic glasses have received considerable attention because of their possible application as structural and functional materials. Kinetic fragility parameter m in amorphous material presents degree of deviations from the Arrhenius law above the glass transition temperature (T_g) of the material. Kinetic fragility parameter (m) and Kauzmann temperature (T_K) in (Ce_(0.72)Cu_(0.28))_(90-x)Al_(10)Fe_x (x = 0, 5 or 10) and Zn_(38)Mg_(12)Ca_(32)Yb_(18) bulk metallic glasses have been determined by differential scanning calorimetry (DSC). Results show that Zn_(38)Mg_(12)Ca_(32)Yb_(18) presents a higher m than (Ce_(0.72)Cu_(0.28))_(90-x)Al_(10)Fe_x (x = 0, 5 or 10). The activation energies Eg for glass transition are 1.51 eV (x = 0), 1.59 eV (x = 5) and 1.83 eV (x = 10) in (Ce_(0.72)Cu_(0.28))_(90-x) Al_(10)Fe_x (x = 0, 5 or 10), and 3.59 eV in Zn_(38)Mg_(12)Ca_(32)Yb_(18), respectively. The values of E_g increase with increasing the Fe content in (Ce_(0.72)Cu_(0.28))_(90-x)Al_(10)Fe_x (x = 0, 5 or 10) bulk metallic glasses. Kinetic fragility parameter m of bulk metallic glasses increases with the glass transition temperature T_g of bulk metallic glasses, in agreement with previous investigations.