Ultra-fast sintered functionally graded Fe/W composites for the first wall of future fusion reactors

Aiming at the realisation of nuclear fusion reactors, the joining of W and steel parts is currently examined. Based on proposals to implement functionally graded steel/W materials (FGMs) in the joint to cope with thermal stresses, the present contribution introduces a novel fabrication method for steel/W FGMs. Electro Discharge Sintering (EDS) was used to consolidate Fe/W powders within milliseconds at atmosphere. Due to the short process time, the formation of detrimental intermetallic Fe-W precipitates is limited compared to established fabrication methods. The current work first presents results of the Fe/W powder processing, then a feasibility study regarding the fabrication of homogeneous and graded Fe/W composites with W volume fractions of 0, 25, 50 and 75 % via EDS is presented. Lastly, the composites are characterised microstructurally, thermo-physically, and mechanically in detail.