The isothermal and isochronal kinetics of the crystallisation of bulk amorphous Pd40Cu30P20Ni10

The amorphous alloy Pd40Cu30P20Ni10 has been produced by water quenching the molten alloy. The kinetics of crystallization has been measured by means of isothermal and isochronal differential scanning calorimetry. The associated microstructural changes have been analyzed using scanning electron microscopy. Special interest has been devoted to the influence of isothermal pre-annealing on subsequent isochronal crystallization kinetics. By applying appropriate isothermal pre-annealing temperatures, nucleation of the crystalline phases takes place to different extents. Accordingly, the initial state for the subsequent isochronal crystallization could be changed gradually with respect to the number of pre-existing nuclei. This leads to a gradual change of the mode of nucleation from site saturation to continuous nucleation during the crystallization. The corresponding change of the kinetic parameters has been used to determine the activation energies of nucleation and growth separately. (Author)