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| Formation and evolution mechanisms of large-clusters during rapid solidification process of liquid metal Al | |
| 作者姓名： | LIU Rangsu DONG Kejun LIU Fengxiang ZHENG Caixing LIU Hairong & LI Jiyong |
| 作者单位： | LIU Rangsu，DONG Kejun，LIU Fengxiang，ZHENG Caixing，LIU Hairong & LI Jiyong Department of Applied Physics，Hunan University，Changsha 410082，China; College of Materials Science and Engineering，Hunan University，Changsha 410082，China; College of Chemistry and Chemical Engineering，Hunan University，Changsha 410082，China |
| 摘 要： | A molecular dynamics simulation study has been performed for the formation and evolution characteristics of nano-clusters in a large-scale system consisting of 400000 atoms of liquid metal Al. The center-atom method combined with pair-bond analysis technique and cluster-type index method (CTIM) has been applied here to describe the structural configurations of various basic clusters. It is demonstrated that both the 1551 bond-type and the icosahedral cluster (12 0 12 0) constructed by 1551 bond-types are dominant among all the bond-types and cluster-types, respectively, in the system and play a critical role in the microstructure transitions of liquid metal Al. The nano-clusters (containing up to 150 atoms) are formed by the combination of some middle and small clusters with distinctly different sizes, through mutual competition by unceasing annex and evolution in a seesaw manner (in turn of obtaining and losing), which do not occur as the multi-shell structures accumulated with an atom as the center and |
| 收稿时间： | 15 September 2004 |
Formation and evolution mechanisms of large-clusters during rapid solidification process of liquid metal Al |
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| LIU Rangsu,DONG Kejun,LIU Fengxiang,ZHENG Caixing,LIU Hairong & LI Jiyong.Formation and evolution mechanisms of large-clusters during rapid solidification process of liquid metal Al[J].Science in China(Physics Astronomy),2005,48(1):101-112. | |
| Authors: | Liu Rangsu DONG Kejun LIU Fengxiang Zheng Caixing LIU Hairong Li Jiyong |
| Affiliation: | 1. Department of Applied Physics, Hunan University, Changsha 410082, China 2. College of Materials Science and Engineering, Hunan University, Changsha 410082, China 3. College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China |
| Abstract: | A molecular dynamics simulation study has been performed for the formation and evolution characteristics of nano-clusters in a large-scale system consisting of 400000 atoms of liquid metal Al. The center-atom method combined with pair-bond analysis technique and cluster-type index method (CTIM) has been applied here to describe the structural configurations of various basic clusters. It is demonstrated that both the 1551 bond-type and the icosahedral cluster (12 0 12 0) constructed by 1551 bond-types are dominant among all the bond-types and cluster-types, respectively, in the system and play a critical role in the microstructure transitions of liquid metal Al. The nano-clusters (containing up to 150 atoms) are formed by the combination of some middle and small clusters with distinctly different sizes, through mutual competition by unceasing annex and evolution in a seesaw manner (in turn of obtaining and losing), which do not occur as the multi-shell structures accumulated with an atom as the center and the surrounding atoms are arranged according to a certain rule. This is the essential distinction of nano-cluster in liquid metal from those obtained by gaseous deposition, ionic spray methods, and so on. Though the nano-clusters differ from each other in shape and size, all of them possess protruding corners that could become the starting points of various dendrite structures in the solidification processes of liquid metals. |
| Keywords: | liquid metal solidification process large-cluster configuration evolution mechanism computer simulation |
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