Development of ultra-fine grained W-(0.25-0.8)wt%TiC and its superior resistance to neutron and 3 MeV He-ion irradiations

W-(0.25-0.8)wt%TiC with equiaxed grain sizes of 50-200 nm and nearly full density of 99% was fabricated utilizing mechanical alloying (MA) in different gas atmospheres of H₂, Ar and N₂ and hot isostatic pressing. Microstructural and mechanical property examinations were conducted before and after irradiations with neutrons at 600 °C to 2 × 10²⁴ n/m² and 3 MeV He-ions at 550 °C to 2 × 10²³ He/m². It is found that TiC additions and MA atmospheres significantly affect grain refinement and baseline mechanical properties. The room-temperature fracture strength takes a maximum of 2 GPa for W-(0.25-0.5)%TiC with MA in H₂ (W-(0.25-0.5)TiC-H₂). At 1400-1700 °C superplastic behavior occurs for W-0.5TiC-H₂, but is suppressed for W-0.5TiC-Ar. No neutron irradiation hardening is recognized in W-0.5TiC-H₂ and W-0.5TiC-Ar. The critical fluence for surface exfoliation by He irradiation for W-0.3TiC-H₂ is more than 10 times as large as that for commercially available W materials. These results suggest that ultra-fine grained W-TiC is capable of improved performance as the spallation neutron source solid target.