单层二硫化钼力学性能温度和手性效应的分子动力学模拟  

Molecular dynamics simulation of effects of temperature and chirality on the mechanical properties of single-layer molybdenum disulfide

作　　者：李明林[1,2] 万亚玲[1] 胡建玥 王卫东[3] 

机构地区：[1]福州大学机械工程及自动化学院,福州350116 [2]福建省高端装备制造协同创新中心,福州350116 [3]西安电子科技大学机电工程学院,西安710071

出　　处：《物理学报》2016年第17期300-308,共9页Acta Physica Sinica

基　　金：国家自然科学基金青年科学基金(批准号:50903017;51205302)资助的课题~~

摘　　要：针对文献中单层二硫化钼力学性能随温度变化趋势的不明确,本文基于Stillinger-Weber原子间势函数,采用经典分子动力学方法对单层二硫化钼在不同热力学温度下(1—800 K)的力学行为进行了单轴拉伸模拟,研究温度和手性对其力学性能的影响.结果表明:单层二硫化钼的杨氏模量、抗拉强度、拉伸极限应变等力学性能均随温度的升高而显著减小;单层二硫化钼的杨氏模量和抗拉强度存在明显的手性效应,而不同手性方向的拉伸极限应变差别不大,可以忽略;温度低于800 K时,不同手性二硫化钼断裂之前受拉加载和卸载均没有明显的相变发生;温度在1 K时,沿锯齿方向受拉的单层二硫化钼在极限强度附近会有明显的局部相变发生,且卸载时相变结构能保持稳定.本文也测量出单层二硫化钼在温度1—800 K下沿扶手和锯齿方向的线膨胀系数.Recently, the effect of temperature on the mechanical property（the Young＇s modulus） of the single-layer molybdenum disulfide（SLMo S2） is shown to be insignificant, which is obviously incompatible with the previously published result, i.e. the Young＇s modulus of SLMOS2 decreases monotonically as temperature increases. Aiming at clarifying the relationships between the mechanical properties of the single-layer molybdenum disulfide（SLMo S2） along the armchair（AC） and zigzag（ZZ） directions and the temperature, classical molecular dynamics（MD） simulations are performed to stretch the SLMo S2 along the AC and ZZ directions at the temperatures ranging from 1 K to 800 K by using the Stillinger-Weber（SW） interatomic potentials in this paper. The mechanical properties of SLMo S2 at the temperatures ranging from 1 K to 800 K, including ultimate strength, ultimate strain, and Young＇s modulus, are calculated based on the stress-strain results obtained from the simulations. Results are obtained and given as follows.（1） The mechanical properties of the SLMo S2, including the ultimate strength and Young＇s modulus, are found to monotonically decrease as temperature increases. Increasing the temperature, the ultimate strength of SLMo S2 in the AC direction drops faster than in the ZZ direction, whereas the Young＇s modulus of SLMo S2 in the ZZ direction decreases quicker than in the AC direction, which means that the chirality effect on the ultimate strength is remarkably different from the Young＇s modulus of SLMo S2. However, the ultimate strain in the ZZ direction at the temperatures in a range from 1 K to 800 K is close to that in the AC direction, which means that the effect of chirality on the ultimate strain is insignificant.（2）Unlike the published results in the literature, the phase transition of SLMo S2 is found to only occur at a temperature of1 K and at the moment of initial crack formation as tensiled along the ZZ direction, and the new phase of quadrilateral structure kee

关 键 词：二硫化钼 力学性能 温度效应 手性效应 

分 类 号：O614.612[理学—无机化学]