碳、碳化硅及硅纳米管熔化与压缩特性的分子动力学研究

MD Studies on the Melting and Compressive Properties of C,SiC and Si Nanotube

采用Tersoff势的分子动力学方法,模拟了(5,5)型单壁碳、碳化硅及硅纳米管的熔化与轴向压缩过程,得到了不同温度下各纳米管的形态、原子径向分布、能量变化以及压缩力-应变曲线。进而,根据模拟结果,分析了它们熔化与压缩特性的差异。研究表明,碳、碳化硅及硅纳米管的熔点分别为6300、5600和2250K左右,它们熔化后分别呈现为网状、疏松的不规则球状以及紧密排布的球状形态;碳、碳化硅或硅纳米管的熔点、比热,熔化热以及承压能力均有碳管>碳化硅管>硅管的排序。

By the Tersoff potential based MD （molecular dynamics） method, the mehing and compression of the （5,5） C, SiC and Si nanotubes are simulated, and the molecular configurations, pair correlation function and energy changes of the nanotubes during the heating-up, as well as their compressive force-strain curve, are obtained. According to the computed results, the differences of their melting and compressive mechanical properties are discussed. It is found that the mehing C, SiC and nanotubes have the net-like, loose sphere-like and compact sphere-like configuration respectively and their mehing points are of about 6300, 5600 and 2250K respectively, and that the C nanotube has the highest mehing point, specific heat and melting heat as well as the highest load support capability, whereas the Si tube has the lowest.