Helium ion irradiation behavior of Ni-1wt.%SiCNP composite and the effect of ion flux

Silicon carbide nanoparticle-reinforced nickel metal (Ni-SiCNP composite) samples were bombarded by helium ions with fluences of 1 × 1016 and 3 × 1016 ions/cm2 at two different fluxes. The microstructural and mechanical changes were characterized via TEM and nanoindentation. Nano-scaled helium bubbles in the shape of spheres were observed in the samples irradiated at high flux and polygons at low flux. The number of helium bubbles increased with the fluence, whereas their mean size remained unaffected. In addition, the nanohardness of the damage layer also increased as the fluence increased. In addition this study suggests that a higher flux results in a higher number of smaller helium bubbles, while showing no obvious effect on the irradiation-induced hardening of the materials.