上海科技大学知识管理系统

Ion irradiation experiments are of importance for investigating irradiation damage of reactor structural materials. However, estimating the irradiation hardening of ion-irradiated materials is difficult due to the limitation of ion penetration depth. In recent years, nanoindentation test has been widely used to study the irradiation hardening of materials, because the continuous stiffness measurement (CSM) mode can obtain the relationship between nanohardness and indentation depth at a very small penetration depth. In this work, the average nanohardness of Hastelloy N alloy irradiated by xenon ion at room temperature was tested by this mode. The results showed that the nanohardness in the irradiated samples was larger than that in the unirradiated sample and this value of irradiated samples is saturated when the irradiation dose is in the range of 0.5 similar to 3.0 dpa. Based on the Nix-Gao model, the indentation size effects (ISE) of unirradiated and irradiated samples were separated from nanohardness measured by nanoindentation. The volume law of mixture model (VLM) was subsequently applied to simulate the measured nanohardness. As the depth of indentation increases, the plasticity affected region (PAR) includes both irradiation damage layer and matrix. Interface parameter was introduced to correct the volume of matrix deformation. The results indicated that the improved VLM model leads to a characteristic relation for the depth dependence of nanohardness that is in excellent agreement with nanoindentation experiments.