CRYSTALLIZATION KINETICS OF FE-NI BASED METALLIC GLASSES

Differential scanning calorimetry is used to study the crystallization kinetics of two commerical Fe-Ni metallic galsses near their glass transition point. For 0.01 <x<0.85 the fraction transformed, x, as a function of time, t, satisfies the Johnson-Mehl-Avrami equation with exponent n varying from 2.8 to 4.3 as the annealing temperature is increased. The activation energies for the crystallization process are estimated from the time to 50% transformation as close to 100 kcal mol-1 and are interpreted as arising from viscous flow. © 1978 Chapman and Hall Ltd.