Thermal stability and evolution of microstructures induced by He irradiation in W–TiC alloys

•The TiC particles were thermally stabile in W–TiC alloys.•The formation of He bubbles was suppressed by the TiC particles in the W–TiC alloys.•Suppression of He bubble formation became prominent as the amount of added TiC increased. Dispersion-strengthened W alloys, W-1%TiC and W-2%TiC, were fabricated by spark plasma sintering (SPS). The thermal stabilities of the secondary-phase TiC particles and microstructures in the W alloys during thermal treatments from 100 to 1000 °C were investigated by positron annihilation techniques. The TiC particles were stable in both W–TiC alloys during the annealing process. Both alloys were irradiated by 5-keV He ions at 900 °C–1.8 × 1021 He/m2. Compared with commercially available pure W, the formation of He bubbles was suppressed by the TiC particles in the W–TiC alloys, and the extent of suppression increased as the amount of added TiC was increased.