液态金属Al快凝过程中纳米级大团簇结构的形成特性模拟研究  

Simulation Study on Formation Characteristics of Nano-clusters During Rapid Solidification Process of Liquid Metal Al

作　　者：董科军[1] 刘让苏[1] 李基永[1] 郑采星[1] 彭平[1] 刘海蓉[1] 卢小勇[1] 

机构地区：[1]湖南大学,湖南长沙410082

出　　处：《稀有金属材料与工程》2003年第11期893-897,共5页Rare Metal Materials and Engineering

基　　金：国家自然科学基金资助项目(50071021)

摘　　要：采用分子动力学方法,对含有400000个Al原子的液态金属大系统在快凝过程中纳米级团簇结构的形成特性进行了模拟研究,并采用原子团类型指数法(CTIM)来描述各种类型的团簇结构组态。结果显示: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;纳米级大团簇(150个原子)是由一些中等原子团结合而成,等原子团由小原子团组成;这种结构与由其它方法获得的纳米级大团簇的结构完全不同,后者是以某一个原子为中心按八面体结构堆积起来的多壳层晶体结构。这些结果正好可以用来解释用不同方法所形成的Al的团簇结构组态之间的本质区别。A simulation study on the formation properties of nano-clusters in a large-scale liquid Al system consisting of 400, 000 atoms has been performed by a molecular dynamics method. And a cluster-type index method (CTIM) has been also used to describe the structural configurations of various clusters. The results demonstrate that the icosahedron clusters (12 0 12 0) and their combines play the most important role in the microstructure transition; the nano-clusters (containing up to 150 atoms) are formed by combining of some middle clusters which also are formed by combining smaller clusters; the structures of these nano-clusters are very different from that of those nano-clusters obtained by evaporation, ionic spray methods, and so on, the latter is formed by the multi-shell crystals accumulated with an atom as the center and the surrounding atoms arranged according to octahedron configuration. These results just can be used to explain the essential distinction between the cluster configurations of Al formed by different ways.

关 键 词：液态金属 快凝过程 纳米团簇结构 计算机模拟 

分 类 号：TG111.4[金属学及工艺—物理冶金]