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

Abstract

Deviation values of specific heat difference ΔCp the Gibbs free energy difference ΔG enthalpy difference ΔH and entropy difference ΔS between the supercooled liquid and corresponding crystalline phase produced by the linear, hyperbolic, and Dubey's expressions of ΔCp and the corresponding experimental values are determined for sixteen bulk metallic glasses (BMGs) from the glass transition temperature Tg to the melting temperature Tm The calculated values produced by the hyperbolic expression for ΔCp most closely approximate experimental values, indicating that the hyperbolic ΔCp expression can be considered universally applicable, compared to linear and Dubey's expressions for ΔCp which are accurate only within a limited range of conditions. For instance, Dubey's ΔCp expression provides a good approximation of actual experimental values within certain conditions (i.e., ξ=ΔCgp/ΔCmp < 2, where ΔCgp and ΔCmp represent the specific heat difference at temperatures Tg and Tm respectively). © 2013 Shanghai University and Springer-Verlag Berlin Heidelberg.