Cu偏析诱导Co团簇结构及性质异常的动力学模拟?
Dynamics simulation on the segregations of Cu induced Co-based cluster structures and their prop erties
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摘要: 采用分子动力学结合镶嵌原子势方法,模拟研究了Cu原子分别分布于基体Co团簇内层和表面构成Cu-Co合金团簇的结构和热力学性质,研究表明,相同数目的Cu原子掺杂到基体中因掺杂层的不同,会诱导内层Co团簇和外层Co团簇结构、能量及熔点表现出巨大差异; Cu原子在团簇各层掺杂位置的差异,会导致原子向低能态位置偏移,但相对移动后后续原子的补位,使团簇结构随温度呈相对无扩散度相变; Cu原子由内层向表面偏析是内层Co团簇与相同原子数比例的外层Co团簇熔点产生巨大差异的主要原因。Abstract: The structure and thermodynamic properties of Cu-Co alloy cluster with Cu atoms distributed in inner layer and outer surface of Co cluster are investigated by the molecular dynamics simulation combining with an embedded atom potential method. The results demonstrate that there are huge differences in structure, energy and melting point between the inner layer and outer surface of Co clusters due to various doping layers comprised of the same number of Cu atoms. The different doping positions of Cu atoms in Co cluster make atoms shift towards lower energy state. However, after relative movement, the supplementary deposition of subsequent atoms leads to the relatively non-diffusive phase transformation of cluster structure. The segregations of Cu atoms from inner layer to outer surface of Co cluster are the main reason for the enormous difference in melting point between the inner layer and outer surface of Co clusters with the same percentage of Cu atoms.
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