外加磁场下铁的形核机理

本文采用直接冷却和两相模拟两种分子动力学方法，研究了外加磁场液态铁凝固过程的影响并将结果与无外加磁场的计算结果进行对比. 外加磁场对凝固过程的影响主要体现在临界温度、能量和径向分布函数. 计算结果表明，铁液的凝固相变过程主要是发生在1500∽1600 K的温度范围；在外加磁场作用下，液态铁的凝固点有明显减小的趋势. 通过对扩散系数和粘度的进一步分析，在外加磁场的存在下，体系的扩散系数增大而粘度减小，研究显示外磁场驱动的铁液原子涨落较强导致凝固点的降低.

Nucleation Mechanism of Iron in an External Magnetic Field

In this work, the solidification of liq-uid iron with or without external magnetic field was investigated by us-ing two molecular dynamics methods, namely direct cooling and two-phase simulation. The influence of external magnetic field on the solidification is characterized by the critical tempera-ture and radial distribution functions. Our computational results show that under external magnetic field, the solidification point tends to decrease significantly. By fur-ther analyzing the diffusion coefficients and viscosity, we attribute the effect to the stronger fluctuation of liquid iron atoms driven by the external magnetic field.