High heat load tests on W/Cu mock-ups and evaluation of their application to EAST device

Tungsten has been considered as the primary candidate plasma-facing materials (PFM) for the EAST device. Three actively cooled W/Cu mock-ups with an interlayer made of tungsten–copper alloy (1.5 mm) were designed and manufactured. The tungsten armors, pure sintered tungsten plate (1 mm) and plasma-sprayed tungsten coatings (0.3 and 0.9 mm), were bonded to the interlayer by brazing and depositing respectively. All mock-ups can withstand high heat flux up to 5 MW/m2 and no obvious failure was found after tests. The thermal performance experiments and microstructure analyses indicated the structure of mock-ups possess good thermal contact and high heat transfer capability. WCu alloy as an interlayer can largely reduce the stress due to the mismatch and improve the reliability. The mock-up with 0.9 mm coating had the highest surface temperature than the other two mock-ups, delaminations of this mock-up were found in the near surface by SEM. The primary results show that pure sintered tungsten brazed to WCu alloy is a possible way, and thick plasma-sprayed coating technique still need to be improved.