NANOINDENTATION TEST ON ELECTRON BEAM-IRRADIATED BORIDE LAYER OF CARBON-CARBON COMPOSITE FOR PLASMA FACING COMPONENT OF LARGE TOKAMAK DEVICE

摘要

The nanoindentation behavior of an electron irradiated boride overlaid on carbon-carbon (C/C) composite for plasma facing components of a large Tokamak device was examined up to the maximum load of 0.3 mN. The scanning electron micrography indicated that the irradiation caused the melt-down and resolidification of thr boron carbide layer. However. it was found by the X-ray diffraction analysis that the layer did nor change its crystalline structure. Young's modulus and mean pressure of the irradiated area were estimated from load-penetration depth (P-h) curves as 270 GPa and 19.2 GPa, respectively, which were 40 and 20% lower than the values for the bulk material. These properties for the unirradiated region were 125 GPa and 3.1 GPa, respectively. only one third and one tenth of thr values fur the bulk. It is attributed to thr porous structure of the unirradiated material. [References: 10]