Thermal shock fatigue behaviors of various W-0.5 wt%ZrC materials under repetitive transient heat loads

Abstract

Thermal shock fatigue resistance behaviors of a series of rolled W-0.5 wt%ZrC materials (WZC) fabricated using tungsten powders with different powder grain sizes of 0.2 μm (0.2WZC), 0.5 μm (0.5WZC) and 2.8 μm (2.8WZC) were investigated by simulating the effects of edge-localized modes in fusion devices like transient heat events on these WZC specimens. The as prepared three different specimens exhibit different cracking thresholds and cracking patterns under repetitive (100 shots) transient heat loads. The cracking thresholds of the as-rolled 0.2WZC and 0.5WZC are in the range of 0.22–0.33 GW/m2, but <0.22 GW/m2 for the case of 2.8WZC. Moreover, recrystallization reduces the thermal shock fatigue resistance and leads to the decrease of cracking thresholds and the increase of cracking densities. Tensile results show that both along the rolling and transverse directions, the as-rolled 0.2WZC and 0.5WZC have the comparable ultimate tensile strengths (UTS) in a relatively high level, but the as-rolled 2.8WZC has smaller ones. The correlation between the thermal shock resistance, microstructures and tensile properties has been proposed.