Material degradation and particle formation under transient thermal loads

Carbon-based materials and metals have been exposed to fusion relevant thermal loads in an electron beam test facility to simulate off-normal plasma conditions such as disruptions or vertical displacement events (VDEs). The erosion process in carbon-based materials is dominated by brittle destruction, a process which is associated with the formation of carbon dust; this process becomes essential at a threshold value of approx. 200 MW m−2. In metals the dominating processes are melting, crack formation in the recrystallized material, and – at higher thermal loads – splashing and boiling of the melt layer. Additional material degradation due to neutron irradiation (up to 0.35 dpa at 350°C and 700°C) and its influence on the high heat flux performance have been investigated.