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采用分子动力学方法,对含有100000个Al原子的液态金属系统在快凝过程中团簇结构的形成及幻数特性进行了模拟研究,采用原子团类型指数法(CTIM)描述了各种类型的团簇结构组态.模拟结果显示:在凝固过程中,二十面体原子团(120120)及其组合在微观结构转变中起着最重要的作用;由不同数目基本原子团的不同组合所形成的不同层次的团簇结构,其尺寸分布具有明显的幻数序列,依次为13(13),19(21),26~28(27),32~33(32),39~40,43~44,48,······等(括号内为液态时的对应值),它们分别依次与由1,2,3,4,5,6,7,······个基本原子团的不同组合所形成的该层次的团簇数的峰值位置相对应.本幻数序列与Harris,Echt及Schriver等人的实验结果相符.
The molecular dynamics method was used to simulate the formation of cluster structure and the magic number property of liquid metal system containing 100000 Al atoms during rapid solidification. Various types of clusters were described by atomic type index method (CTIM) The results show that in the solidification process, the icosahedral (120120) and its combinations play the most important role in the microstructure transformation. The different levels of the different combinations of elementary radicals The cluster structure has a significant magic number sequence in the order of 13 (13), 19 (21), 26-28 (27), 32-33 (32), 39-40, 43-44, ··············· (corresponding values in brackets for liquid state), which respectively followed by different combinations of 1, 2, 3, 4, 5, 6, 7, ... basic radicals Which corresponds to the peak position of the number of clusters at this level.The present sequence of magic numbers is consistent with the experimental results of Harris, Echt and Schriver et al.