Effect of stored energy and recovery on the overall recrystallization kinetics of a cold rolled low carbon steel

The evolution of recrystallization kinetics of a cold rolled low carbon steel with an initial coarse grain size and heterogeneous microstructure is studied by means of nucleation and interface-averaged grain boundary migration rate. Recrystallization is governed by two annealing time ranges, characterized by two Avrami exponents. Range 1 is associated to the recrystallization of high stored energy regions mostly belonging to the γ-fiber and Range 2 to the progression of recrystallization mainly through low stored energy α-fiber grains. The transition from Range 1 to Range 2 is consistent with the decrease of high stored energy regions. Afterwards, recrystallization is very sluggish due to the low stored energy regions remaining in the material and leads to incomplete recrystallization for annealing times of practical significance. Additionally, coercive field measurements are used to infer the evolution of concurrent recovery with recrystallization. Recovery only accounts for a small part of the decrease of the total stored energy, the rest being due to the heterogeneous distribution of the stored energy.