氦对钛的体胀及稳定性影响的分子动力学模拟

采用分子动力学(molecular dynamics，MD)方法研究了不同压力下氦-空位复合物的大小、氦含量对材料肿胀、稳定性的影响. 分析了影响材料体积改变及稳定性因素：随着氦含量的增加，体系内聚能减小，系统体积膨胀，稳定性降低；当氦-空位复合物较小时，随着氦-空位复合物的增大，体系内聚能增加，系统体胀减小，体系趋于稳定. 当氦泡中氦原子达到一定数量时氦泡不再继续长大. 关键词： 体胀 氦-空位复合物 钛 分子动力学

Influence of helium on volume change and stability of titanium structure: An atomistic simulation

Molecular dynamics was employed to study the effects of the size of helium cluster and the helium content on the elastic properties and the volume change of the material under different pressures. We tried to analyse the cause that induced volume change of titanium and the instability of the system. With the increasing of helium content, the cohesive energy reduces, the external volume of the material expands, and the materials becomes unstable. When the size of He cluster is small, with the helium bubble growing, the cohesive energy rises, a volume contraction of the material occurs, and the system tends to keep stable. When the number of helium atoms in helium bubble is over 74, it is difficult for the helium bubble to grow.