液态Al80Fe20合金的中程有序结构

利用分子动力学模拟（MD）与X射线衍射实验相结合的方法研究了Al80Fe20合金熔体的微观结构，发现在结构因子的小角部分（Q=17.5 nm－1）出现了一个明显的预峰（FSDP），且模拟值与实验值吻合得很好，这被认为是熔体中存在中程有序（MRO）的标志.通过对化学短程序参数(CSRO)α及Bhatis Thornton（BT）结构因子的分析计算，发现熔体中存在较强的化学序，并认为正是这种化学序导致了中程有序结构的产生. Faber Ziman（FZ）偏结构因子的SFe－Fe(Q)和SAl－Fe(Q)在Q=17.5 nm－1处分别存在最大值与最小值，也是熔体中存在着超结构的表征.给出了体系的配位数及代表中程有序的原子团簇的结构模型.

Medium-range Order Structure in Liquid Al80Fe20 Alloy

The microstructure of liquid Al80Fe20 alloy is studied by molecular dynamics simulation, combined with experiment of X ray diffraction. It is found that there exists an obvious prepeak in the small domain（Q=17.5 nm－1）of the structure factor, which is considered as indicative of the existence of medium range order(MRO) in the liquid. Furthermore, the results of MD simulation agree also well with those of experiment. The chemical short range order(CSRO) α and Bhatis Thornton(BT) partial structure factors show that there exists very strong CSRO in the liquid, which suggests that the CSRO result in the formation of MRO. The maximum and the minimum at Q=17.5 nm－1 in SFe－Fe(Q) and SAl－Fe(Q) of Faber Ziman(FZ) partial structure factors also indicate the existence of superstructure in the liquid. We also calculate the coordination numbers of the system and give a structural model representing MRO clusters.