Growth of recrystallized nuclei in Nb added ultra-low carbon steel sheets

The growth of the recrystallized nucleus in niobium added ultra-low carbon steel was investigated experimentally by restricting the nucleation sites. Moreover, the growth process of the recrystallized nucleus from the layered deformed microstructures with various deformed state were simulated by a multi-phase-field (MPF) method, for comparison with the experiments. The cold-rolled microstructure was a layered structure, consisting of both α-fiber close to cube orientation and γ-fiber, and the re-crystalline nucleus tended to grow up preferentially along deformed γ-fiber. The simulations suggested that the shape of growing nucleus was influenced by the dislocation density or layered distances of deformed structures, which were related to the cold-rolling reduction. Furthermore, the crystal rotation of the re-crystallized grains at the middle stage of recrystallization was tried to be simulated using another phase field simulation.