The isothermal and isochronal kinetics of the crystallisation of bulk amorphous Pd 40Cu 30P 20Ni 10

Abstract

The amorphous alloy Pd 40Cu 30P 20Ni 10 has been produced by water quenching the molten alloy. The kinetics of crystallisation has been measured by means of isothermal and isochronal differential scanning calorimetry. The associated microstructural changes have been analysed using scanning electron microscopy. Special interest has been devoted to the influence of isothermal pre-annealing on subsequent isochronal crystallisation 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 crystallisation 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 crystallisation. The corresponding change of the kinetic parameters has been used to determine the activation energies of nucleation and growth separately.