The free volume kinetics during structural relaxation in bulk Pd-P based metallic glasses

Isothermal enthalpy relaxation and density relaxation were investigated for bulk Pd42.5Cu30Ni7.5P20 and Pd40Ni40P20 metallic glasses. The density was measured at room temperature after relaxing the sample for a given time. Enthalpy relaxation data of Pd42.5Cu30Ni7.5P20 glass and density relaxation data of Pd40Ni40P20 glass were well fitted by a non-Debye type relaxation function. A fit to a stretched exponential relaxation function of density relaxation data at 549 K of Pd40Ni40P20 glass gave the exponential index of 0.66. Isochoric Kauzmann temperature TK was estimated from density measurements for nearly fully relaxed bulk glasses and TK = 456 ± 10 K was obtained.