微观相场模拟B2­FeAl金属间化合物有序畴界的形成和迁移

摘要

基于微观相场动力学理论，建立 B2型金属间化合物的沉淀动力学方程，研究 Fe­Al 合金时效处理时B2­FeAl有序畴界的形成和迁移。结果表明： B2­FeAl金属间化合物有序畴的形核孕育期随时效温度的升高而延长，随Al含量的增加而缩短；有序畴的长程序参数随时效温度的升高而降低，随Al含量的增加而先增大后减小；有序畴界始终向其曲率中心运动，且在曲率较大的地方其运动速率较大；有序畴界的迁移遵循 Rm(t)−Rm(0)=kt (m≈2)，m 受合金成分和时效温度的影响很小，但k 的绝对值随着Al含量的降低而减小，随时效温度的升高而增大。%The precipitation kinetics function of B2 type intermetallic compound was established based on the microscopic phase­field kinetics theory,and it was used to investigate the formation and the motion of B2­FeAl ordered domain boundaries during aging of Fe­Al alloy. The results demonstrate that the nucleation incubation period of B2­FeAl ordered domains becomes longer with the increase of aging temperature,and it becomes shorter with the increase of Al content. The long­range order parameter of ordered domains decreases with the growth of aging temperature,and it first increases then decreases with the increase of Al content. The ordered domain boundaries move to their own centre of curvature all the time, and they move faster at where the curvature of ordered domain boundary is bigger. The rule Rm(t)−Rm(0)=kt (m≈2) is obeyed when the ordered domain boundaries migrate, the value of m is affected very slightly by aging temperature and alloy composition, but the absolute value of k decreases with the decrease of Al content,increases with the increase of aging temperature.