Analysis of Al nanocrystals nucleation in Al$_{87}$Ni$_8$Y$_5$ metallic glass under constant heating rate conditions

The process of formation of a nanocomposite amorphous-nanocrystalline structure in Al$_{87}$Ni$_8$Y$_5$ metallic glass under heating with rate of 0.083 K/s was investigated by differential scanning calorimetry, electrical resistance measurements and X-ray diffraction. Taking into account the features of the nanocomposite structure, the model for nucleation rate changes $J(T)$ determination using the experimentally estimated changes of size and volume fraction of nanocrystals was proposed. The dependence of $J(T)$, obtained in this way, was analyzed in the frames of the classical equation of temperature dependence of homogeneous nucleation rate. The numerical values of the parameters in this equation, resulting for the best agreement with the experiment, were determined, and possible reasons of discrepancies were discussed.