Material degradation and particle formation under transient thermal loads

Carbon-based materials and metals have been exposed to fusion relevant ther mal loads in an electron beam test facility to simulate off-normal plasma c onditions such as disruptions or vertical displacement events (VDEs). The e rosion process in carbon-based materials is dominated by brittle destructio n, a process which is associated with the formation of carbon dust, this pr ocess becomes essential at a threshold value of approx. 200 MW m(-2). In me tals the dominating processes are melting, crack formation in the recrystal lized 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 degreesC and 700 degreesC) and its influence on the high heat flux performance have been investigated. (C) 2001 Elsevier Science B. V. All rights reserved.