Abstract
Carbon-carbon composites are deemed as candidate materials for applications in very high temperature reactors (VHTRs). In a VHTR, carbon-carbon composite materials would experience severe environmental impacts of both a high radiation fluence (about 3 × 10 16 /cm 2 per year) and high temperatures (∼1200 °C), and radiation damage is accordingly expected. In this study, samples prepared from a three-dimensional pitch-based carbon-carbon composite material were irradiated with a 4 MeV C 2+ ion beam emitted by an accelerator to deliberately induce various levels of radiation damage on the samples at 1000 °C. Transmission electron microscopy analyses were then conducted to examine the evolution of microstructures in the samples, and a scanning electron microscope was used to examine the changes in surface morphology. It was found that an accumulated fluence of 7.0 × 10 21 /m 2 at 1000 °C resulted in cracks between the matrix and the fiber in the sample. These interfacial cracks were all parallel to the fiber orientation. The fiber/matrix bonding strength might play an important role in the mechanical property of the carbon-carbon composite material. In the meantime, cracks were also found at the fiber side of the sample irradiated under the same condition. © 2011 Elsevier Ltd. All rights reserved.