Strong liquid behavior of Pr55Ni25Al20 bulk metallic glass

The dynamic viscosities of the supercooled and superheated liquids for Pr55Ni25Al20 bulk metallic glass-forming alloy were measured as a function of temperature by the three-point beam bending and oscillating vessel methods, respectively. It was found that the viscosity over the entire experimental temperature interval could be well fitted by the Cohen-Grest relation, and the supercooled liquid of Pr55Ni25Al20 alloy behaved much closer to strong glasses than the other reported metallic glasses. The differences of entropy, enthalpy, and Gibbs free energy between the supercooled liquid and the crystal for Pr55Ni25Al20 alloy were calculated based on the specific heat capacity. It is shown that the glass-forming ability is correlated more strongly with the liquid-crystal Gibbs free energy difference than with the fragility parameter m. (c) 2006 Elsevier B.V. All rights reserved.