Progress in the Development of CFC/CuCrZr Components for HL-2M Divertor

The HL-2M divertor consists of a flat-type carbon fiber composite (CFC)/CuCrZr component and a cassette structure. The CFC/CuCrZr component is made of a water-cooled CuCrZr heat sink armored with carbon CFC tiles. The CFC surface was modified by using Cr slurry to improve its wettability to copper. The Cr layer was deposited by a simple screen-printing technique and then sintered at 1300 °C in a vacuum furnace. An oxygen-free copper (OFC) buffer layer was cast on the modified CFC surface in order to mitigate the internal stresses caused by mismatch in the coefficient of thermal expansion of CFC and CuCrZr. The brazing of the cast OFC/CFC tiles to the CuCrZr heat sink was performed by using a silver-free brazing alloy. Microstructural observations and shear strength tests demonstrate high quality of joining for the CFC/CuCrZr joints. The brazed CFC/CuCrZr mock-up experienced cyclic loading tests of 7 MW/m
²
for 1000 cycles with no degradation of heat removal, which meets the requirement of HL-2M divertor.