Studies of He irradiated tungsten using transmission electron microscope

Tungsten (W) as one of the potential plasma-facing materials (PFMS) in the nuclear fusion reactors would suffer severe irradiation which can result in deterioration of properties. Understanding the irradiation effects on PFMS is thus critical to improve their performances. Here, the He irradiation effects is studied by focusing on microstructures of the W surfaces. As the irradiation fluence increases, surface morphologies of W become rough with abundant nano-structures, namely nanotendrils. Transmission electron microscope (TEM) images show these nanotendrils contain lots of He voids, which reveals good deformation behavior albeit brittle.