Morphology and crystalline evolution of tungsten induced by low-energy helium ions irradiation
The responses of polycrystalline tungsten to low energy helium ions irradiation were investigated. SEM and AFM measurements revel that nano-scale helium bubbles formed on the surface of tungsten at earlier stage. The size and number of the formed helium bubbles increase with the increase of helium fluence until they break. Mass loss and sputtering yields analysis indicated that the surface spalling caused by the damage of helium bubbles is the main format of tungsten damage. Helium atom is shown to be not energetically favorable to dissolve, self-trap and cluster at (101) surface in comparison to (111) and (001) surface.
KeywordsIrradiation damage Tungsten Surface morphology Crystalline He bubble
The project was supported by Liaoning Provincial Natural Science Foundation guiding Plan (Nos. 201602189, 20180510006) and Dalian Science and Technology Star Project (No. 2017RQ149).