Evaluation of advanced tungsten alloys under high particle flux and intense transients in the DIII-D tokamak

Experiments are planned to test several advanced tungsten alloys under reactor-relevant conditions using the Divertor Material Evaluation System (DiMES) in the DIII-D tokamak. These materials are promising candidates for plasma-facing components in future fusion devices in terms of reduced intrinsic brittleness, hydrogenic retention and surface degradation compared to ITER-grade tungsten (IGW). The effects of high heat and particle fluxes on DiMES samples of tungsten fiber reinforced tungsten (Wf/W) composites [1], micro-structured tungsten, recrystallized and dispersoid-strengthened tungsten alloys (W/ZrC dispersoids [2] and W/SiC [3]) are studied against the performance of IGW. A large disk of Wf/W composite will be exposed to repetitive thermal loading in a tokamak divertor for the first time to examine long range (~3.5 cm) crack formation and mechanical behavior of the material. The post-characterization of the material surfaces will focus on gross erosion, hydrogenic retention, and surface changes such as crack formation, recrystallization, chemical composition and surface bonding of redeposited material.

[1] J.W.Coenen, PS 96 (2021) 124063

[2] J.L.Barton, NME 20 (2019) 100689

[3] T.Abrams, NF 61 (2021) 066005