【摘要】 采用分子动力学(MD)方法,结合原子间多体势函数,模拟了bcc铁(αFe)在高压下向hcp铁(εFe)转变的过程,并与实验数据进行了比较.系统的压强通过计算维里压强获得,并通过Berendsen方法进行调整和改变.还采用相同的原子间势模拟bcc和hcp两种不同结构的铁,对高压下铁相变的机制和相变压强进行直接的计算和模拟,以对采用的原子间势进行更严格的检验和修正.模拟计算得到超高压下(>15GPa)两种结构的PV曲线图以及hcp铁的c/a值等相关结果,都与实验结果有较好的符合.而在较低压下(0～15GPa)PV关系中常用的铁的原子间势对bcc铁仍有很好的模拟效果,而对hcp铁则效果不是很理想.因此,铁的原子间势还有待进一步改进.更多还原

【Abstract】 Molecular dynamics method (MD) is used to investigate the iron bcc to hcp phase transition under high pressure,and the simulative results are compared with experimental results.Many-body inter-atomic potential is chosen to calculate inter-atomic force.The pressure of the system is obtained by calculating virial pressure of the system,and is adjusted via the Berendsen method.The relation of P-V and the ratio c/a of iron has been obtained and compared favorably with experimental results.Simulating two crystal structures simultaneously posts higher requirements to the chosen inter-atomic potential and can help the development of more accurate potentials.The simulation of bcc structure agreed to the experimental results perfectly.But the result of hcp structure is not satisfying.So,the atomic potential of Fe needs more improvements.更多还原