金属表面下氦泡融合与释放研究

Study of the coalescence and release of helium bubble under metal surface

采用分子动力学方法研究了钛金属表面下不同深度处氦泡的行为,分析了氦泡融合与释放的竞争,对比了不同深度处氦泡的释放对金属的影响.结果表明:在接近金属表面处,氦泡很难通过融合无限长大,当达到临界尺寸后,氦泡将会释放而不再与邻近的氦泡发生融合;植入深度对氦泡的融合有一定的影响,深度越大,越有利于形成具有较高氦密度的大氦泡;较深处氦泡的释放会在金属表面形成较大的突起和表面针孔.实验中观察到的不同尺寸的表面孔,其部分原因来自于金属表面下不同深度处氦泡的释放.

The behavior of helium bubble under titanium surface at different depths has been studied using molecular dynamics method.The competition of helium bubble release and coalescence was analyzed,and the effects of helium bubbles release at different depths were compared.The results show that the helium bubbles are difficult to grow unlimitedly by coalescence.Release would occur when the bubble attains a critical size.The effect of implantation depth on helium bubble coalescence is that,the greater depth is conductive to the formation of a larger helium bubble with a high helium density.The release of a helium bubble at deeper depth would form a larger protrusion and leave a larger surface pinhole on the metal surface.The surface poles with different sizes were observed in experiments,part of the reason came from the release of helium bubbles at different depths.