论文部分内容阅读
采用分子动力学方法模拟了半径从0.3—1.3nm变化的小尺寸铝纳米团簇的熔化、凝固行为.基于势能-温度曲线、热容-温度曲线分析,获得了熔点、凝固点与尺寸的依变关系,并利用表面能理论、小尺寸效应开展了现象分析.研究表明,铝团簇原子数小于80时,熔点和凝固点的尺寸依赖性出现无规律的异常变化;而大于该原子数,熔、凝固点则随着团簇尺寸的减小而单调下降;当原子数为27时,团簇熔点高于块材熔点近40K.同时,铝纳米团簇呈现出凝固滞后现象,即凝固点低于熔点.
The molecular dynamics simulation was used to simulate the melting and solidification behavior of small size aluminum nanoclusters with varying radius from 0.3 to 1.3 nm. Based on the potential energy-temperature curves and heat-mass-temperature curve analysis, the melting point, solidification point and size dependence were obtained And the phenomenon has been analyzed by surface energy theory and small size effect.The results show that when the number of aluminum clusters is less than 80, the size dependence of melting point and freezing point appears irregular variation, while when the number of aluminum clusters is larger than the number of atoms, When the number of atoms is 27, the melting point of the cluster is higher than the melting point of the block by about 40 K. At the same time, the aluminum nanoclusters show a solidification hysteresis, that is, the freezing point is lower than the melting point.