CRYSTALLIZATION OF ALUMINUM-BASED METALLIC GLASSES - PROCESSES AND KINETICS

Differential scanning calorimetry was used to study the crystallization processes and kinetics of melt-spun Al90Y10, Al90Fe5Y5 and Al85Fe7.5Y7.5 metallic glasses. The characteristics of structural relaxation and glass transition have been observed only in the two ternary alloys. All the glasses have a relatively high thermal stability. The isothermal experiments show that the application of Johnson-Mehl-Avrami theory is limited to the late crystallization processes, particularly for the two low concentration alloys. The crystal nucleation and growth in the early stage devitrification of the glasses are discussed in terms of the local Avrami exponent.