针对核反应堆燃料包壳材料锆合金在服役过程中存在的辐照硬化和辐照生长等现象，本研究开展了300℃下1.8 MeV氩离子不同剂量辐照Zr-Sn-Nb合金实验（辐照损伤峰值分别为2、5、10、24 dpa）。通过辐照区微观结构（位错环、氩气泡和第二相粒子）分析与微纳力学实验相结合，系统阐释了微观缺陷演化与辐照硬化行为的关联机制。研究结果表明：氩离子辐照后的Zr-Sn-Nb合金主要形成了以<a>型位错环和高密度氩泡为主的辐照缺陷，其中<a>型位错环尺寸随剂量增加呈持续增长趋势，密度在峰值损伤为10 dpa时达到饱和；氩泡的形核具有明显的辐照剂量依赖性，其密度与尺寸均随剂量增加而显著上升，当损伤值为24 dpa时氩泡尺寸增长至最大（约2.48 nm）；低剂量辐照后第二相粒子呈现非晶化，其几何特征（尺寸分布、空间密度）不随辐照剂量发生变化。通过对比纳米压痕与TEM原位压缩实验，结合Nix-Gao与弥散障碍硬化（DBH）模型分析，证实位错环-氩气泡对位错运动的协同阻碍效应是导致Zr-Sn-Nb合金辐照硬化的主要原因。此外，上述两种表征技术获得的辐照硬化趋势呈现一致性，又各有侧重点，本研究采用“微观表征-力学测试-模型解析”的分析方法为锆合金辐照损伤评估提供方法学参考。

To address irradiation-induced hardening and growth in zirconium alloys for nuclear cladding, this study investigated Zr-Sn-Nb alloys irradiated by 1.8 MeV Ar+ ions at 300°C (corresponding to peak damages: 2, 5, 10, 24 dpa). By integrating microstructural characterization of irradiation-induced defects (dislocation loops, argon bubbles, and secondary phase particles) with micromechanical testing, the correlation between defect evolution and irradiation hardening mechanisms was systematically elucidated. The results indicated that irradiation defects are dominated by <a>-type dislocation loops and high-density argon bubbles. The size of <a>-type dislocation loops exhibited continuous growth with increasing dose, and their density saturated at 10 dpa. Argon bubble nucleation displayed significant dose dependence, with both density and size increasing markedly with irradiation dose. The average bubble size reaches the largest value of ~2.48 nm at 24 dpa. Secondary phase particles underwent amorphization under low-dose irradiation, while their geometric characteristics (size distribution and spatial density) remained unchanged. A comparative investigation based on nanoindentation measurements and in-situ TEM uniaxial compression tests, supported by theoretical frameworks including the Nix-Gao model and dispersed barrier hardening (DBH) theory, revealed that irradiation-induced hardening in Zr-Sn-Nb alloys predominantly arises from the synergistic interaction between dislocation loops and argon bubbles. Furthermore, the irradiation hardening trend derived from nanoindentation measurements was statistically consistent with that obtained from in-situ TEM compression tests. The proposed "microstructure-mechanics-modeling" methodology provides a systematic framework for evaluating irradiation damage in zirconium alloys.