Property Degradation of Helium Ion Irradiated Tungsten Thin-Film Alloys

Plasma-facing materials (PFMs) in a nuclear fusion reactor are exposed to high heat flux and energetic particles, so radiation damage-tolerant materials need to be systematically investigated and developed. Although tungsten-based alloys with nanocrystalline structures have been reported to mitigate radiation-induced damages effectively, vast combinations of microstructures and compositions need to be investigated to discover novel PFMs with the ideal set of properties. Trial-and-error-based traditional irradiation experiments can be inefficient to explorer the huge design space. In this study, we utilize a combinatorial approach that allows efficient characterizations of composition-microstructure-dependent irradiation damage behaviors of nanocrystalline W-based alloys. Structural, thermal, and mechanical properties were analyzed before and after He-ion irradiation experiments for W-Re-Ta thin-film alloys with composition spreads. We find that the distribution of He-based defects can be significantly altered by the solute concentrations Ta and Re in W, which critically affects the property changes upon irradiation.