金属Ni纳米线凝固行为的分子动力学模拟

采用EAM镶嵌原子作用势，通过经典的分子动力学模拟方法研究了不同冷却速度下的金属Ni纳米线的凝固行为，并给出了纳米线在凝固区域的结构演变过程.利用键对分析技术研究了在不同冷却速度下体系中的原子团簇在降温过程中的变化情况.研究表明，纳米线的凝固起始于表面原子，并且随着冷却速度的降低，Ni纳米线的微观结构从非晶态过渡到多壳螺旋结构，最终达到稳定的面心立方结构.多壳螺旋结构同时具有确定的结晶温度和长程无序、短程有序的非晶结构的特征. 关键词： 纳米线 凝固行为 分子动力学 键对分析

Freezing of Ni nanowires investigated by molecular dynamics simulation

The freezing of Ni nanowires at different cooling rates was studied by classical molecular dynamics simulation via embedded atom potential method. The structure evolution of Ni nanowires in the freezing region was also presented. In order to distinguishing the local clusters in the cooling process of Ni nanowires formed at different cooling rates the bond, pair analysis is employed. The simulation results indicate that the freezing of the nanowires starts from the surface and the structure of the nanowires changes from amorphous to fcc crystal via helical multi-shelled structure along with the decrease of cooling rate. The helical multi-shelled structure possesses not only the short-range order and long-range disorder of amorphous structure but also a definite crystallization temperature.