The development of joining doped graphite to copper for first wall application in HT-7 tokamak

Two joining methods have been developed for joining carbon based plasma facing material to copper based heat sink material for the potential application in HT-7 and EAST tokamak. The first joining method is based on brazing technique by using a rapidly solidified foil-type Ti–Zr based amorphous filler with a melting temperature of 850 °C. The other joining method is direct active metal casting–casting the premixed powders of copper and active transition metals on the mechanical machined carbon surface directly. SEM observations demonstrate high quality of joining surface for both joints. The brazing technique is more promising for fabrication joint with larger size compared with the direct active alloy casting method. High heat flux test using an e-beam device was performed on the actively cooled C/Cu joint fabricated by brazing method. There has no damage occurred on the joint after heat loading at 6 MW/m2.