Influence of cyclic thermal loading on brazed composites for fusion applications

Reactor grade graphite and molybdenum (TZM) were brazed with different high temperature brazes. The resulting tiles had a size of 50 × 50 mm² with a graphite thickness of 10 mm and a TZM thickness of 5 mm. The brazed composites have been tested in electron beam simulation for their thermal fatigue properties. The parameters of these tests were chosen to match NET design specifications for normal operation and "slow" peak energy deposition. The resulting damage and microstructural changes on the graphites and the brazes are discussed. Additional information is supplied on X-ray diffraction data proving the presence of different phases in the brazes.