Abstract

Helium bubble growth and coalescence in the slip plane as well as the influence on substrate were studied using the molecular dynamics method. In the slip plane, the helium bubbles grow first along the slip plane and then grow toward the side which is short one atomic layer in the form of a hexagonal structure at low temperature. The growth rates of helium bubbles are related to the addition rate of helium atoms and their surrounding environments. After coalescence, the coalesced helium bubble grows first toward the side that is short one atomic layer. Then it grows along the slip plane with a velocity less than the growth rate before coalescence. Helium bubble growth and coalescence in the slip plane have significant influence on the substrate. During the process, the preexisting slipping metal atoms are pushed back to the normal lattice sites, and the crystal structure of the metal is recovered around the helium bubbles. The recovered area changes with the number of helium atoms in the bubble and the temperature of the substrate. The simulation results indicate that the preexisting grain boundary is beneficial for enhancing the helium damage resistance of metal.

摘要

使用分子动力学方法研究了滑移面中氦气泡的生长和聚结以及对底物的影响。在滑移面中，氦气泡首先沿滑移面生长，然后在低温下以六方结构的形式向短一个原子层的一侧生长。氦气泡的生长速度与氦原子的添加速度及其周围环境有关。聚结后，聚结的氦气泡首先向短一个原子层的一侧生长。然后它沿着滑移面以小于合并前的增长速度的速度增长。滑移平面中氦气泡的生长和聚结对基板有显着影响。在这个过程中，预先存在的滑动金属原子被推回到正常的晶格位置，并且在氦气泡周围恢复了金属的晶体结构。回收面积随气泡中氦原子数和基板温度的变化而变化。模拟结果表明，预先存在的晶界有利于提高金属的抗氦损伤能力。