Comparison of dislocation densities of primary and secondary recrystallization grains of Si-Fe

Abstract Single crystals of Si-Fe ( 3 1 4 per cent Si) were cold-rolled and annealed to obtain both primary and secondary recrystallization structures. The dislocation densities of the primary and secondary recrystallization grains were measured by an etch-pit method, which also disclosed considerable variation in etchpit density among the primaries and in many instances within individual primaries. The average dislocation densities were 2 × 107 lines/cm2 for primaries and 2 × 106 lines/cm2 for secondaries, which indicates that primaries on the average are less perfect than secondaries. The effects of the observed difference in dislocation density on the driving force for growth in the initial and also in the later stages of secondary recrystallization were considered. Calculations indicate a critical size for growth of a grain in deviating orientation which is substantially above the average size of primaries. The difference in dislocation density contributes approximately 8 per cent to the driving force of a large secondary in the Si-Fe studied.