Correlation Between Radiation Damage Evolution and Mechanical Properties of Fe-Irradiated Tungsten

Tungsten is a promising plasma-facing material for fusion applications; however, irradiation-induced damage can significantly affect its structural, surface, and mechanical properties. In this work, polycrystalline tungsten was irradiated with 84 MeV 56Fe ions at fluences of 1 × 1015, 5 × 1015, and 1 × 1016 ions cm−2. Radiation damage was evaluated using SRIM/TRIM simulations and correlated with scanning electron microscopy, X-ray diffraction, surface roughness measurements, and nanoindentation results. The calculated projected range of Fe ions was approximately 5.57 μm, while the maximum damage increased from approximately 1.38 to 13.79 dpa with increasing fluence. SEM revealed increasingly pronounced surface modifications at higher fluences. XRD confirmed preservation of the body-centered cubic α-W structure without detectable additional phases, although small non-monotonic changes in the lattice parameter and diffraction peak widths were observed. Surface roughness showed a non-monotonic dependence on fluence, reaching maximum mean values of Ra = 0.083 μm and Rz = 0.880 μm at 5 × 1015 ions cm−2. Nanoindentation showed a tendency toward lower mean hardness and elastic modulus values after irradiation, although the differences were generally comparable to the experimental scatter. Overall, the results demonstrate a complex relationship between accumulated radiation damage and the structural, surface, and nanomechanical response of tungsten.