High-temperature brazing of tungsten with steel by Cu-based ribbon brazing alloys for DEMO

摘要

The designs of DEMO components require the joining of low-activation steel (for example RUSFER EK-181, EUROFER, etc.) with tungsten. One of the most critical parameters is the thermal expansion mismatch between tungsten and steel, which can lead to the failure of components during use or even after manufacturing. In this paper, high-temperature brazing of EK-181 steel with tungsten was carried out. Pure copper was used for the direct joining of steel with tungsten. Brazing alloys based on copper (Cu-Ge and Cu-Ti) rapidly quenched into ribbon were used with a vanadium interlayer. Brazing was carried out in vacuum furnaces at 1100 degrees C for 20 min. The structural-phase states of the joints obtained were studied, the microhardness measured, shear strength tests carried out and thermocycling tests performed in the range 700-25 degrees C.