Microstructural simulations of dynamic recrystallization

A Monte Carlo model for the simulation of static recrystallization and grain growth has been adapted for dynamic recrystallization by adding recrystallization nuclei and stored energy continuously with time. The results of the simulations have shown that many of the essential features of dynamic recrystallization are reproduced. The stored energy of the system, which may be interpreted as the flow stress, goes through a maximum and then decays, monotonically under some conditions and otherwise in an oscillatory manner. The principal parameters that were varied were the rate of adding stored energy, Delta H, and the rate of adding nuclei, Delta N. As Delta H increases, for fixed Delta N, the oscillations decay more rapidly and the asymptotic stored energy rises. As Delta N increases, again the oscillations decay more rapidly but the asymptotic stored energy decreases. The mean grain size of the system also oscillates in a similar manner to the stored energy but 90 deg out of phase. Necklacing of the prior grain structure by new grains is observed for low Delta H and high Delta N; it is however, not an invariable feature of grain refinement, i.e., cases where the dynamic grain size is smaller than the initial grain size. All these results were obtained without the addition of special parameters to the model such as a critical strain for the initiation of recrystallization.