Theoretical analysis of the interconnection between the shear elasticity and heat effects in metallic glasses

• Changes of the shear modulus and heat effects in metallic glasses are considered.
• Interstitialcy theory and elastic dipole model are used for the analysis.
• Both approaches provide explanation for elasticity changes and heat effects.

Changes of the shear modulus and heat effects occurring upon structural relaxation and crystallization of metallic glasses are analysed within the framework of two approaches, the Interstitialcy theory and elastic dipole model. The former approach assumes that elastic and heat effects are determined by dumbbell interstitial defects inherited from the melt. The analysis within this framework is based on the postulate that the internal energy change is proportional to the shear modulus and defect concentration change. The elastic dipole model takes into account that dumbbell interstitials are in fact elastic dipoles and the change of the internal energy is determined by their elastic strain fields, which are considered within the framework of non-linear theory of elasticity. In spite of fully different phenomenology, both approaches lead to very similar theoretical expressions for the elastic and heat effects. The interconnection between these approaches, their advantages and problems are discussed.