Fatigue properties and fracture mechanism of 2D C/C composite materials

Sumita, Junya ; Shibata, Taiju ; Tachibana, Yukio ; Kuroda, Masatoshi*

An application of higher heat-resistant ceramic material to the control rod of VHTR is required for the VHTR development, since the core components of the VHTR will be subject to the severer condition than that of the HTGR. The carbon fiber reinforced carbon composite (C/C composite) is one of the major candidate materials as substitute for the metallic materials which has been generally used for the control rod of nuclear reactors. In this study, tension-compression fatigue tests have been carried out by using two types of the 2D-C/C composite (made by Toyo Tanso and Tokai Carbon) to obtain the design data for VHTR. The microstructure of the ruptured specimens was also observed to clarify the fracture mechanism of the 2D-C/C composite. As a result, the fatigue properties were almost the same between the two types of the 2D-composite. On the other hand, the fracture mechanism was different between them depending on their matrix property.