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.