An analysis of the solute drag effect of Nb on recrystallization of ultralow carbon steel

The solute drag effect of Nb on recrystallization of Fe has been investigated using the mathematical model which can calculate the velocity of moving grain boundaries based on thermodynamics. The calculation result has shown that Nb retards the migration of grain boundary during recrystallization due to the solute drag effect. The driving force dissipated by the solute drag was compared to that by pinning effect of fine precipitates. The simulation results imply that the dominant process is dependent on total driving force and Nb concentration: the dominant phenomena are only the pinning effect for small total driving force and the Nb content less than the critical composition, both effects for small total driving force and the Nb content over than the critical composition, and only the solute drag effect for large total driving force and the Nb content over than the critical composition. Both effects do not operate in such a case that the total driving force is large and the Nb content is less than the critical composition.