Surface damage during transient thermal load of 50% thickness reduced W-2% (Vol.) Y2O3 sheet with different recrystallization volume fraction

Abstract

Thermal shock damage of tungsten as a plasma facing material (PFM) depends on thermal shock power density level, duration and repeated time, and microstructure of the sample. The recrystallization process will degrade the mechanical property of material and thus change the its thermal shock resistance. The effects of recrystallization volume fraction on thermal shock response of W-Y2O3 under different power density levels (0.22–0.44 GW/m2) has been systematically studied. Electron beam pulse of duration of 1 ms with 100 recycles was used to simulate the transient thermal load of fusion device. The changes of morphology, distance, depth, width of crack and surface roughness on the rolling direction-normal direction (RD-ND) surfaces of W-Y2O3 samples with different recrystallization volume fraction were investigated. The results showed that recrystallization process have significant influence on the thermal shock resistance of W-Y2O3 samples. For the rolled sample, crack depth, width and surface roughness increased with the increased of power density level while crack distance decreased. The partially and fully recrystallized samples showed significant wider crack networks and severe surface modification.