High Heat Flux Exposures of Recrystallized and Additively Manufactured Tungsten Samples on DIII-D*

Additively manufactured (AM) tungsten (W) samples were tested under high heat fluxes in the divertor of DIII-D alongside ITER-grade W. The materials demonstrated comparable thermo-mechanical response and surface damage. AM refractory metals can enable complex designs of components that are not achievable through normal manufacturing approaches. To evaluate their robustness to high heat loads in DIII-D, the W samples were angled at ~17° towards the incident heat flux. Materials included high-density AM W and W-Re(3%) as well as partially recrystallized ITER-grade W. The Divertor Materials Evaluation System (DiMES) was used to expose samples to 5 H-mode discharges with ELMs for a total of 10 s. Pre-exposure modeling using SMITER and SIERRA/Aria codes allowed for careful selection of heat flux parameters to ensure surface damage but avoid bulk melting. The inter-ELM heat flux varied between ~8 – 17 MW/m² on the angled surfaces. ELMs contributed additional heating up to 30 MW/m² at ~40 Hz. Initial observations confirm surface cracking and recrystallization and the successful avoidance of melt damage. The AM W-Re(3%) showed significantly less surface damage compared to the pure AM W. Extensive microscopy and thermal analysis is underway and will be presented.