The helium behavior and thermal stability of W/Ta bilayer nanocomposite were investigated by neutron reflectometry. The results show the W/Ta interface is stable after He⁺ ion irradiation and annealing. Under He⁺ ion irradiation, the helium enriched and denuded sublayers are formed at W/Ta interfacial region, due to the migration of helium from the W layer towards the Ta layer. That results from the lowest He solution energy and electron density of Ta layer, and negative energy barrier from W to Ta layer. This mechanism enlightens us that dispersing Ta-nanoparticles into tungsten can relieve helium deleterious effect in tungsten.

中文翻译：

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用中子反射法研究 W/Ta 双层纳米复合材料的氦行为和热稳定性

通过中子反射法研究了W/Ta双层纳米复合材料的氦行为和热稳定性。结果表明W/Ta界面在He ⁺离子辐照和退火后是稳定的。在 He ⁺离子辐照下，由于氦从 W 层向 Ta 层迁移，在 W/Ta 界面区域形成了富氦和脱氦亚层。这是因为 Ta 层的 He 溶液能量和电子密度最低，以及 W 到 Ta 层的负能垒。这种机制启发我们，将 Ta 纳米粒子分散到钨中可以减轻氦对钨的有害影响。