Disruption erosions of various kinds of tungsten

Thermal shock experiments on CVD-W, powder sintered tungsten (P-W), monocrystal tungsten (M-W) and brush tungsten (B-W) have been performed under the heat flux of 1000-2400 MW m(-2) with the pulse length of 2 ms in JAERI electron beam irradiation system (JEBIS). The samples were exposed to a single pulsed beam with the electron energy of 70 keV and preheated up to 1000 degrees C. In these experiments, the following information was obtained: (1) CVD-W is the most promising from an erosion point of view; (2) the increased weight loss was mainly caused by severe particle emission; (3) weight loss for every kind of tungsten was greater at 1000 degrees C than at room temperature; (4) no cracks were observed at 1000 degrees C for every sample by SEM observation; (5) secondary cracks were observed along the rolled direction at room temperature and may cause: the exfoliation of a piece of tungsten surface during normal operation. (C) 1998 Elsevier Science S.A. All rights reserved.