Nanoindentation investigation of ion-irradiated Fe-Cr alloys using spherical indenters

The performance of materials exposed to high doses of neutron radiation is currently of great interest for the development of nuclear fusion energy production. An Fe12%Cr alloy was subjected to high-dose (6 dpa) radiation with 2MeV Fe+ ions to simulate the damage structures caused by neutron radiation, resulting in a damage layer similar to 0.7 mu m in depth from the surface. Spherical nanoindentation, using indenters with radii of 5, 10, and 20 mu m, was used to determine reliable values for the initial yield pressure, the evolution of plastic deformation and the elastic modulus of this material, in the irradiated and unirradiated condition. The results showed that the initial yield pressure within the damage layer can be determined and was approximately a factor of two higher than that of the same material in the unirradiated condition. The irradiated material appeared to display strain softening following yield.