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采用分子动力学方法对Al50Mg50合金熔体的快速凝固过程进行了模拟,并采用双体分布函数、键型指数法和原子团类型指数法等方法,从微观结的不同层面对Al-Mg合金熔体快速凝固过程中微观结构的演化机理进行了深入的分析研究.结果表明:本模拟所获得的Faber-Ziman偏结构因子与实验结果符合较好.Al50Mg50合金熔体具有遗传性,在快速凝固过程形成了非晶态结构,其中二十面体短程序结构对非晶态结构的形成起决定性作用.基于原子团类型指数法的团簇分析表明,Al50Mg50非晶态合金的微观结构由许多不同结构类型的短程有序结构单元构成,其中二十面体基本原子团是其主要的短程有序结构单元,短程有序区包含各种不同尺寸的团簇结构.其微观结构不能采用Bernal模型来表征.
The rapid solidification process of Al50Mg50 alloy melt was simulated by molecular dynamics method. The Al-Mg alloy melt (Al-Mg alloy) was melt at different layers of microstructure by the methods of cataract distribution, bond index and atomic group index. The results show that the Faber-Ziman partial structure factor obtained by this simulation is in good agreement with the experimental results.Al50Mg50 alloy has the inheritance of the evolution and forms during the rapid solidification process The non-crystalline structure, in which the icosahedral short structure structure plays a decisive role in the formation of amorphous structure.The cluster analysis based on the atomic group index method shows that the microstructure of Al50Mg50 amorphous alloy is composed of many short-range Ordered structure unit, in which the icosahedral elementary radicals are the main short-range orderly structural units, and the short-range order region contains clusters with different sizes. The microstructure can not be characterized by the Bernal model.