利用纳米压痕仪的连续刚度测量模式测试了常温氙离子辐照后Hastelloy N合金的纳米硬度。结果表明，辐照样品的纳米硬度均大于未辐照样品的纳米硬度，且辐照剂量在0.5~3.0 dpa这一范围内时，辐照样品的纳米硬度处于饱和状态。在Nix-Gao模型的基础上，分离出未辐照样品和辐照样品的压痕尺寸效应，并通过VLM (volume law of mixture)模型来模拟实验测得的纳米硬度。由于随着压头压入深度的增加，塑性影响区中将同时包含辐照损伤层与基体，在VLM模型中引入“界面参数”(χ)以修正基体的形变量，改进后的模型能够更好地模拟纳米压痕的实验结果。

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 0.5~3.0 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.