The effect of transient nucleation behavior on thermal stability of Fe48Co32P14B6 metallic glass

Abstract

Abstract The experimental isothermal kinetic curves for Fe48Co32P14B6 glass measured in the temperature range 683 to 714\xa0K have been analyzed with using the analytical equation derived as a combination of the integral form of Kolmogorov’s equation of mass crystallization kinetics and the Kashchiev’s transient nucleation model. The transient nucleation rates show the trend to the steady-state values with increasing of annealing temperature. From a combination of the kinetic data and the values of crystal growth velocity, U, determined from the structural data, the steady-state nucleation rate values have been estimated. These data are analyzed within the classical nucleation theory and the work of the critical nucleus formation and the specific interfacial free energy values have been calculated. It has been established that transient behavior of nucleation rate in Fe48Co32P14B6 glass results in an increase of the onset crystallization time by 6.4 to about 3 times at 683 and 714\xa0K, respectively. The temperature dependence of the transient time in the glass investigated is compared with that of the effective diffusivity as well with the similar data found for Fe40Ni40P14B6 and Fe40Co40P14B6 glasses and the possible reason of the observed changes in the degree of non-stationarity of nucleation rate has been discussed.