Determination of accurate theoretical values for thermodynamic properties in bulk metallic glasses

Abstract

Deviation values of specific heat difference $ \Updelta C_{\rm p},$ the Gibbs free energy difference $ \Updelta G , $ enthalpy difference $ \Updelta H , $ and entropy difference $ \Updelta S $ between the supercooled liquid and corresponding crystalline phase produced by the linear, hyperbolic, and Dubey’s expressions of $ \Updelta C_{\rm p}$ and the corresponding experimental values are determined for sixteen bulk metallic glasses (BMGs) from the glass transition temperature $ T_{\text{g}} $ to the melting temperature $ T_{\text{m}}. $ The calculated values produced by the hyperbolic expression for $\Updelta C_{\rm p}$ most closely approximate experimental values, indicating that the hyperbolic $\Updelta C_{\rm p}$ expression can be considered universally applicable, compared to linear and Dubey’s expressions for $ \Updelta C_{\rm p},$ which are accurate only within a limited range of conditions. For instance, Dubey’s $\Updelta C_{\rm p}$ expression provides a good approximation of actual experimental values within certain conditions (i.e., $ \xi = \Updelta C_{\rm p}^{\rm g}/\Updelta C_{\rm p}^{\rm m}< 2 , $ where $\Updelta C_{\rm p}^{\rm g}$ and $\Updelta C_{\rm p}^{\rm m}$ represent the specific heat difference at temperatures $ T_{\text{g}} $ and $ T_{\text{m}} , $ respectively).

Keywords

Bulk metallic glass (BMG) / Specific heat / Linear expression / Hyperbolic expression