Precise measurement of density in the isothermal relaxation processes of Pd42.5Cu30Ni7.5P20 and Zr 50Cu40Al10 glasses

Abstract

The isothermal relaxation processes of bulk Zr50Cu 40Al10 and Pd42.5Cu30Ni 7.5P20 glasses were examined by density reduction associated with relaxation. Density experiments were carried out by buoyancy method at room temperature. The isothermal relaxation curves were best fitted by a stretched exponential function with a Kohlrausch exponent less than unity. Based on free volume model, the reduced free volume xf/as = 0.0355 and flow defect concentrationCf/as= 5.80 × 10-13 in as-quenched state was obtained for Pd42.5Cu 30Ni7.5P20 glass. However, the temperature at which the free volume started to deviate from equilibrium concentration on cooling of the melt was not in accordance with calorimetric glass transition temperature. © 2007 The Japan Institute of Metals.