Kinetic and thermodynamic studies of the fragility of bulk metallic glass forming liquids

Abstract

The thermodynamic functions of the bulk metallic glass (BMG) forming Pd43Ni10Cu27P20 alloy are determined calorimetrically as a function of temperature. Along with eight other BMG forming alloys, the available experimental thermodynamic and viscosity data are reassessed. For each alloy, consistent Vogel–Fulcher–Tammann (VFT) fits of the viscosity measurements are established, and the temperature dependence of the configurational entropy is calculated from thermodynamic data. Together with the VFT fits, fits to the Adam–Gibbs equation are performed using this configurational entropy change. We find remarkable agreement between the Adam–Gibbs and VFT fits. Moreover, the temperature T0 is obtained from the VFT fits at which the viscous flow diverges. This T0 matches very well the temperature where the configurational entropy vanishes in the corresponding Adam–Gibbs fits.