Cold Spray Deposition and Additive Manufacturing of Fusion First Wall Materials*

Tungsten (W), tantalum (Ta), and Ta/W composites produced using cold-spray (CS) and laser bed fusion additive manufacturing (AD) have been evaluated as potential fusion first-wall materials, optimized for low porosity and impurity content. Deuterium (D) retention was tested with thermal desorption up to 1280 K on samples exposed to 95 eV plasma at the PSI-2 facility, with fluences up to 3x10²⁵ D/m². Pure Ta CS coatings showed significantly higher retention compared to sintered W, due to Ta's exothermic hydrogen absorption. Increased W content reduced D retention in CS coatings, indicating the feasibility of its tailoring for fusion applications. D retention in AD W was measured to be 3x of that in reference W. Post-exposure analyses revealed that CS and AD materials suppressed D blister formation and remained stable after annealing. Scanning Electron Microscopy, X-ray Photoelectron Spectroscopy, and X-ray Diffraction analyses were performed for morphology, contamination, sub-surface composition, and crystallinity; results will be presented. Pre-characterization was also performed for high heat flux tests planned at the DIII-D tokamak. This research enhances commercial viability of wall material fabrication/repair techniques and improves tools for erosion and retention modeling.