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In this paper, the method of molecular dynamics, combined CaMg pair distribution function, the key index and clusters type index (CTIM) on microstructure characterization methods, the system studied liquid alloy in the process of rapid solidification microstructure formation and evolution mechanism . First, the new environment of semiconductor materials Mg 2 Si, Ca 2 Si is briefly introduced, and density functional theory-based first-principles pseudopotential plane wave method more detailed calculations on the the block body CaMgSi the electronic structure and optical properties. And in considerable detail the basic principles of the method of molecular dynamics and liquid, amorphous microstructure characterization methods. The first simulation study of the solidification process of containing 10,000 atoms in the liquid the CaMg alloy system. The results show that: under the conditions of 1 × 10 12 K / s cooling rates, the system is formed as the main body of 1551,1541 and 1431 bond type amorphous structure and their glass transition temperature of about 530K. Of which (120,120) radicals play a decisive role in the formation of the amorphous structure in the process of rapid solidification. While the the clusters structural stability not only related to the basic type of atomic group constituting the clusters, and also related to the connection between the type of central atom as well as the central atom. Further study of the different cooling rate during rapid solidification of liquid CaMg alloy microstructure of. 1 × 10 11 K / s, 1 × 10 12 K / s, 1 × 10 to 13 K / s, 1 × 10 14 K / s four cold-speed conditions, the amorphous structure. With the reduction of the cooling rate, the basic radical increase in the number of corresponding increase in the short-range order structure. Meanwhile, the cooling rate of the basic hereditary radicals (120,120) have an important impact, lower cooling rate system (120,120) higher hereditary basic cluster at low temperatures. Containing 50,000 atoms larger liquid the CaMg alloy system during rapid solidification simulation to study the formation and evolution of larger clusters. The results show that: 1 × 10 12 K / s cooling rate conditions, in the process of the formation and evolution of the nano-cluster structure in high temperature clusters can not form a stable group clusters of the main body portion, the lower its hereditary. Clusters in the low temperature formation of a stable body portion, and its structure has a high hereditary. Throughout the evolution, the corner part of the structure of the medium-range ordered clusters instability, hereditary. The results of these studies, further study of the new environment of semiconductor materials Mg 2 Si, Ca 2 Si provide new ideas, and for ternary system CaMgSi to lay a solid foundation.
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