On the Nature of the Excess Internal Energy and Entropy of Metallic Glasses

Abstract

The excess internal energies ΔUQ and excess entropies Delta {{S}_{Q}} of ten metallic glasses with respect to their parent crystalline states are determined from calorimetric studies. The elastic energy ΔUel of the subsystem of interstitial defects responsible for relaxation phenomena in metallic glasses according to interstitialcy theory is calculated within this theory using the measured high-frequency shear modulus. It is established that the quantities ΔUQ and ΔUel coincide with each other within an accuracy of no less than 10–15%. It is concluded that the excess internal energy and excess entropy of metallic glasses are due primarily to the elastic energy of the subsystem of interstitial defects. The dissipation of this energy into heat under heating reduces ΔUQ and ΔSQ to zero because of the complete crystallization. The entropy per defect is estimated from calorimetric data as Sd ≈ (20–30)kB, which is characteristic of interstitial defects.