钨基辐照材料纳米氦泡诱导位错成核的分子模拟

基于分子动力学模拟,系统研究纳米氦泡的内压、孔径和温度对钨基辐照材料位错成核机理的影响.首次采用微动弹性带(nudged elastic band,NEB)方法对氦泡诱导位错成核的能垒进行分析.研究发现,存在一个极限氦/空位比,当氦/空位比超过该极限值时,纳米氦泡通过内压驱动位错成核、位错竞争与反应、交滑移等微观机理生...

Molecular simulation of dislocation nucleation induced by nanosized helium bubbles in irradiated tungsten materials

Based on molecular dynamics simulation, the effects of helium bubble pressure, bubble size, and bubble temperature on the mechanism of dislocation nucleation in irradiated tungsten materials are investigated. The nudged elastic band (NEB) method is applied to analyze the energy barrier of dislocation nucleation induced by a helium bubble for the first time. An ultimate value of the helium/vacancy ratio is determined. When the helium/vacancy ratio exceeds this ultimate value, a nanosized helium bubble is generated and a prismatic dislocation loop is formed and grows, through dislocation nucleation driven by high internal pressure, dislocation competition and reaction, and dislocation cross-slip. The ultimate internal pressure required for dislocation nucleation induced by the helium bubbles decreases with the increase in temperature and the growth of the helium bubbles. Increasing the helium/vacancy ratio can effectively reduce the energy barrier required for dislocation nucleation.