液态铝基合金微观结构及其性质的分子动力学模拟研究

利用分子动力学研究了液态铝基合金Al80Fe20和Al80Cu20在 800~2200K温度范围内的微观结构和性质的变化。扩散系数的计算结果显示两合金有着不同的动力学行为。温度大约1400K以下液态Al80Cu20的扩散系数随温度的变化比Arrhenius关系所预期的要慢些，所得结果与Brillo研究小组的实验结果基本一致。当液态铝基合金的动力学发生异常变化时，其微观二十面体短程序的含量和作用也发生相应的变化。因此，熔体的奇特动力学行为可能由于其微观局域结构短程序随着温度的变化而异常地改变而引起的。

Molecular dynamics simulations of atomic transport property and structure in Al-based alloys

By performing the molecular dynamics simulations, we have investigated the dynamical properties and microstructures of Al80Fe20 and Al80Cu20 alloys from 2200 to 800 K. The dependence of selfdiffusion coefficients with temperature shows different dynamical behaviors in Al-based melts. However, the change of diffusion with temperature is slower than the expected from the Arrhenius relationship in liquid Al80Cu20 alloy below about 1400 K, which is in general agreement with the experimental result of Brillo et al. When the dynamical property exhibits the anomalous behavior, the role of icosahedral cluster has transformed in the corresponding Al-based melts. The abnormity in the dynamical properties of melts can be attributed to special topological change of clusters in melts.