Journal
JOURNAL OF PHYSICS-CONDENSED MATTER
Volume 33, Issue 43, Pages -Publisher
IOP PUBLISHING LTD
DOI: 10.1088/1361-648X/ac18f1
Keywords
metallic glasses; relaxation; defects; thermodynamic potentials
Categories
Funding
- Russian Science Foundation [20-62-46003]
- Russian Science Foundation [20-62-46003] Funding Source: Russian Science Foundation
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By performing calorimetric and shear modulus measurements on bulk metallic glasses, this study demonstrates the consistency between the calorimetric determination and calculation of excess thermodynamic potentials, with a focus on the physical origin of these potentials being related to a system of interstitial-type defects frozen-in from the liquid state. The estimates of defect formation enthalpy and entropy indicate that the enthalpy scales with the shear modulus while the entropy is significantly large, aligning with the basic assumptions of the interstitialcy theory.
We performed calorimetric and shear modulus measurements on four bulk metallic glasses upon heating up to the temperature of the complete crystallization as well as in the fully crystallized state. On the basis of calorimetric experiments, we calculated the excess thermodynamic potentials with respect to the crystalline state-the enthalpy Delta H, entropy Delta S and Gibbs free energy Delta phi-as functions of temperature. Using high-frequency shear modulus measurements we show that calorimetric determination of Delta H, Delta S and Delta phi is consistent with the calculation of these potentials within the framework of the interstitialcy theory (IT) within a 15% uncertainty in the worst case for all MGs under investigation. It is concluded that the physical origin of the excess thermodynamic potentials in MGs can be related to a system of interstitial-type defects frozen-in from the liquid state upon melt quenching as suggested by the IT. The estimates of the defect formation enthalpy H (f) and entropy S (f) show that H (f) scales with the shear modulus while S (f) is quite large (10 k (B) to 20 k (B)), in line with the basic assumptions of the IT.
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