Understanding thermal effects and the evolution of the defect concentration based on shear modulus relaxation data in a Zr-based metallic glass

A relationship between thermal effects and relaxation of the high-frequency shear modulus upon heat treatment of bulk Zr48(Cu5/6Ag1/6)44Al8 metallic glass has been found. This relationship is attributed to the relaxation of the interstitial-type defect system frozen-in from the melt upon glass production. Calorimetric data show that the thermal effects of metallic glasses occurring on heating include heat release below the glass transition temperature, heat absorption above it and heat release caused by crystallization. The equation derived from the Interstitialcy theory can be used to calculate the shear modulus relaxation using the above calorimetric data. The obtained results are used to trace the defect concentration as a function of temperature and thermal prehistory.