3D Heat Flux and Melt Motion Analysis of Angled Tungsten Samples on DIII-D

Dispersoid-strengthened tungsten (DSW) offers an avenue for increasing the recrystallization resistance of tungsten (W) alloys at higher temperatures. Thermal analysis is presented for a high heat flux exposure of angled (15°) DSW and ITER-grade W samples in the DIII-D tokamak. Recrystallization, cracking, and melting of both materials was observed as well as dispersoid evaporation. The exposure was performed using the Divertor Materials Evaluation System (DiMES) at DIII-D. Samples endured 9 H-mode discharges with ELMs. The inter-ELM heat flux ??_⊥ strongly varied from ~11 – 24 MW/m² on the angled surfaces. ELMs contributed up to 115 MW/m² at ~40 Hz. Consequently, two of the samples nearest the strike point melted. The resulting melt motion was radially inward in the ?????? direction at ~20 mm/s. About 10 mm³, or ~50%, of the exposed geometry was displaced due to melt motion. EBSD microscopy shows uniform recrystallization throughout the sample depth. SMITER and SIERRA/Aria codes are used to estimate ??_⊥, temperature evolution, melt formation, and ?????? melt motion.