KINETICS OF ABNORMAL GRAIN-GROWTH IN PURE IRON

Grain growth after primary recrystallization in unstrained and strained specimens of pure iron is examined during isothermal anneals at three different temperatures (664, 680, 690° C). Undeformed specimens undergo continuous grain growth, while the deformed ones show a stage of rapid discontinuous growth. The peculiar characteristics of the abnormal growth kinetics, and in particular the presence of three well-defined stages of growth, are brought out by plotting, versus annealing time, the ratio between the mean grain diameters of deformed and undeformed samples. The parameters n (exponent of the kinetic equation) and Q (apparent activation energy) are determined. © 1979 Chapman and Hall Ltd.