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Ag-Cu双金属团簇中Ag原子偏析行为的分子动力学研究

发布时间:2018-03-11 06:42

  本文选题:Gupta势 切入点:分子动力学 出处:《原子与分子物理学报》2017年04期  论文类型:期刊论文


【摘要】:采用恒温分子动力学方法系统模拟研究了不同尺寸不同组分的Ag-Cu双金属团簇的退火过程.分析低温退火结构可得团簇中Ag原子的偏析行为:在Ag原子所占比率较少时,Ag原子全部占据在团簇表面;随着Ag原子数的增多,直到Ag和Cu的比率接近时,绝大多数Ag原子仍占据在团簇表面;这与实验观测Ag-Cu混合团簇中Ag原子的偏析行为完全一致.通过细致研究Ag-Cu双金属团簇中Ag原子的偏析行为与团簇尺寸、组分和温度的关系发现:当Ag原子所占比重明显少于Cu原子时,在各不同尺寸下,Ag原子偏析温度点均高于熔点,即在熔点以上一定温度范围内仍会出现Ag原子的偏析现象;当Ag原子所占比重明显多于Cu原子时,在各不同尺寸下,体系偏析温度点均低于团簇熔点;对于较大尺寸团簇,在Ag原子所占比重接近于Cu原子时,体系偏析温度点与团簇熔点相同.
[Abstract]:The system of constant temperature molecular dynamics simulation of the annealing process of Ag-Cu with different sizes and different components of bimetallic clusters. Analysis of low temperature annealing structure and segregation behavior of Ag atoms in the clusters: the proportion of less in the Ag atom, Ag atom on the surface of all clusters; with the increase in the number of Ag atoms. The ratio of Ag and Cu until the close, most of the Ag atoms still occupy in the cluster surface; the segregation behavior and experimental observation of Ag-Cu mixed clusters of Ag atoms in the same way. Through detailed research and cluster size segregation of Ag-Cu bimetallic clusters of Ag atoms, found that the relationship between composition and temperature. When the proportion of Ag atoms accounted for less than Cu atoms, in different sizes, Ag segregation temperature point higher than the melting point, the segregation phenomenon in a certain range of temperature above the melting point will appear Ag atoms; when the proportion of Ag accounted for the atom When the Cu atoms are significantly more than the Ag atoms, the segregation temperature points of the system are lower than the cluster melting points under different sizes. For larger size clusters, when the proportion of the Cu atoms is close to that of the Cu atoms, the segregation temperature of the system is the same as that of the clusters.

【作者单位】: 新疆大学物理科学与技术学院;
【基金】:国家自然科学基金(11164029)
【分类号】:O562


本文编号:1597018

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