Blistering of tungsten films deposited by magnetron sputtering after helium irradiation

In this paper, tungsten films were deposited on tungsten substrates by magnetron sputtering and some films were annealed at 1273 K for 1 h. Subsequently, the morphology and microstructure of as-deposited and pre-annealed films were measured by scanning electron microscopy and X-ray diffraction. In addition, both films were exposed to helium ions with energy of 60 keV and fluence of 1.0 × 1022 m−2 at room temperature. After helium irradiation, the blisters formed on surface of films induced by helium irradiation were observed by scanning electron microscopy. Here we report the differences in blistering on surface between as-deposited and pre-annealed films. In addition, in spite of similar microstructure of both films including grain size and preferred orientation, the different compressive stresses within both films lead to the different behaviors of blistering.