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利用第一性原理分子动力学模拟对Cu45Zr55-xAlx(x=3,7,12)块体非晶合金熔体在快速冷却为玻璃态过程中原子结构的演变进行了系统的研究.结果显示,以Al为中心的二十面体是合金熔体在液—固转变过程中最稳定的原子团簇结构,可视为该合金系中的基本结构单元;以Al为中心的稳定团簇的数量和在空间中的组成形式决定了该合金微观结构的非均匀性和原子扩散能力的大小,这也是影响合金宏观力学性能和玻璃形成能力的关键因素.
The first-principles molecular dynamics simulations were used to systematically study the atomic structure evolution of Cu45Zr55-xAlx (x = 3,7,12) bulk amorphous alloy melt during rapid cooling into glassy state. The results show that, The Al-centered icosahedron is the most stable atomic cluster structure of the alloy melt during liquid-solid transformation and can be regarded as the basic structural unit in this alloy system. The number of stable clusters centered at Al and The composition of space determines the microstructure heterogeneity and atomic diffusion capacity of the alloy, which is also a key factor affecting the macroscopic mechanical properties and glass forming ability of the alloy.