USE OF KOLMOGOROV-JOHNSON-MEHL-AVRAMI KINETICS IN RECRYSTALLIZATION OF METALS AND CRYSTALLIZATION OF METALLIC GLASSES

The Kolmogorov-Johnson-Mehl-Avrami (KJMA) relation does not compensate for simultaneous recovery that occurs during recrystallization, and KJMA plots for recrystallization in cold-worked metals frequently show severe negative curvature. However, reasonably linear KJMA behavior does occur in recrystallization of some metals and in crystallization of metallic glasses, but considerable variation occurs in the slopes of KJMA plots. This evidence suggests that linear KJMA behavior may occur during recrystallization in metals when either a deformed matrix decays to an effectively constant state of recovery or the recovery rate decreases at a constant rate. Linear behavior also may occur during crystallization when the amorphous matrix remains in an essentially constant state of disorder. Analysis of factors that may contribute to this variation indicates that linear KJMA plots may not be indicative of truly linear kinetic behavior. Therefore, caution should be exercised in the use and interpretation of KJMA plots. © 1990.