Structural relaxation in a bulk metallic glass

Differential scanning calorimetry has been used to investigate the structural relaxation in a bulk metallic glass designated Vit 4. Results indicate that Vit 4 has a broad glass transition region with a glass transition temperature of approximately 621 K and an activation enthalpy of 834 kJ/mol. Despite the broad transition region, Wunderlich’s model suggests that structural relaxation in Vit 4 involves the cooperative motion of a single bead. The relaxation behavior was well described by the Tool–Narayanaswamy equation, with x and β values not significantly different from other glass formers. The dynamic and thermodynamic fragility of Vit 4 is compared with other glasses.