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采用分子动力学方法对液态Ca70Mg30合金快速凝固过程中纳米团簇结构的形成和演变特性进行模拟。采用原子团类型指数法(CTIM)对凝固过程中纳米团簇结构的演变进行分析。结果表明:系统在5×1011K/s的冷速条件下形成以1551、1541和1431为主的非晶态结构,非晶转变温度约为530 K;(12 0 12 0)二十面体基本原子团对系统非晶结构的形成起到决定性的作用,并且原子半径较小的Mg原子更容易占据二十面体基本原子团中心原子的位置;同时,纳米团簇主要是通过中等尺寸团簇的合并而形成,纳米级大团簇的形成演变过程呈现出类似于非晶晶化过程的3个阶段式的变化。
Molecular dynamics simulation was used to simulate the formation and evolution of nanoclusters during the rapid solidification of liquid Ca70Mg30 alloy. The evolution of nanoclusters during solidification was analyzed by atomic type index (CTIM). The results show that the system is mainly composed of 1551, 1541 and 1431 amorphous phases at a cooling rate of 5 × 10 11 K / s with an amorphous transition temperature of about 530 K. The (12 0 12 0) icosahedral elementary radicals Which plays a decisive role in the formation of the amorphous structure of the system, and the Mg atoms with smaller atomic radius are more likely to occupy the central atoms of the icosahedral elementary radicals. Meanwhile, the nanoclusters are formed mainly through the combination of medium-sized clusters , The formation and evolution of nanoscale large clusters show a three-stage change similar to the amorphous crystallization process.