No abstract

The values of linear growth velocities of the eutectic colonies in the temperature range of 679–717 K have been determined for the first time from the electron microscopic studies of the partially crystallized samples of Fe48Co32P14B6 metallic glass. Using these data, the values of the effective diffusion coefficients governing growth have been calculated. It has been established that the temperature dependence of the effective diffusivity in Fe48Co32P14B6 glass is well approximated by an Arrhenius law and their values in the temperature range of crystallization are about 2–3 orders of magnitude smaller than those in the Fe40Ni40P14B6 commercial glass. The values of the effective diffusion coefficients at the onset crystallization temperature have been determined, the correlation between pre-exponential factors and activation energies has been found. It has been shown that the parameters which characterize the effective diffusivity in the glass investigated are in good agreement with the published data for the eutectically crystallizing metallic glasses. It has been established that the physical reason of the enhanced thermal stability of the FeCo-based glass compared with that of Fe40Ni40P14B6 is the lower atomic mobility at the glass/crystal interface.