热变形低碳钢中奥氏体静态再结晶介观尺度模拟

采用晶体塑性有限元（CPFEM）和元胞自动机（CA）耦合的方法模拟了热变形低碳钢的静态再结晶．CPFEM的计算结果定量描述了介观尺度上奥氏体变形储能的不均匀分布，为模拟再结晶的形核和长大提供了依据，从而在再结晶CA模型中考虑了不均匀变形的影响．模拟结果显示：变形储能分布不均匀使得再结晶在不同位置的形核密度不同，形核集中在晶界以及晶内储存能较大的区域；随着临界形核储能的降低，形核数量增加，再结晶晶核的位置分布趋于均匀．对不同形核判据下的再结晶动力学也作了讨论．

SIMULATION OF STATIC RECRYSTALLIZATION OF HOT DEFORMED AUSTENITE IN A LOW CABON STEEL ON MESOSCALE

The static recrystallization of hot deformed austenite in a low carbon steel was simulated by coupling a cellular automaton (CA) approach with a crystal plasticity finite element model (CPFEM) on mesoscale. The local stored energy of deformation simulated by CPFEM was incorporated in the CA model as the driving force for subsequent recrystallization nucleation and grain growth. The effect of the inhomogeneous distribution of the stored energy on the static recrystallization was involved, which was difficult for the traditional recrystallization CA models. The simulated results revealed that the density of recrystallization nucleation varied in different sites due to the inhomogeneous distribution of stored energy, and the nuclei concentrated both at the grain boundaries and in the heavily deformed grain interiors. The number of recrystallized nuclei increased and the distribution of the nucleation inclined to homogeneity with decreasing critical stored energy for nucleation. In addition, the recrystallization kinetics under various nucleation criteria was also discussed.