Quantifying recrystallization nucleation and growth kinetics of cold-worked copper by microstructural analysis

Microstructural evolution data describing the recrystallization of cold-worked copper at 394 K (121°C) were obtained by quantitative metallography using scanning electron microscopy and electron backscattered pattern analysis. Using the microstructural path method (MPM), a new analytical representation of the microstructure was devised that emulated all the measurements and successfully explained why simpler representations failed to adequately describe the kinetics of recrystallization in copper. Saturation of preferentially located nucleation sites such as at deformation bands, grain boundaries, etc., where recrystallized grains may cluster in planar arrays before the deformed volume is completely consumed, and time-dependent growth rates matched fully the kinetic behavior of copper during recrystallization. The kinetic behavior of individual texture components (random and cube + cube twin) was also delineated, experimentally and analytically. Precise matching of the analytical representation of the microstructure to experiment allowed calculation of nucleation and growth parameters. These showed that the cube + cube twin grains nucleated at a faster rate than the random grains, that site saturation occurred sooner for the cube + cube twin grains, and that cube + cube twin grains grew at rates about 1.5 times faster than the random grains. The calculations suggested that as recrystallization approached completion, the number of random grains slightly outnumbered the cube + cube twin grains.