9Cr ferritic/martensitic steels are promising materials for in-core components in advanced Gen-IV reactors. In these applications, their long-term microstructural stability under thermal exposure and resistance to neutron irradiation are essential. Tempered (unaged) and long-term thermal aged T92 samples were used to evaluate the effects of thermal aging and ion irradiation on the microstructure and micromechanical properties of the steel. Both the tempered and aged samples were irradiated with 3 MeV Fe¹¹⁺ ions to 0.25, 0.50, 1.00 and 5.00 dpa at room temperature. Using the nanoindentation technique, the irradiation hardening behaviors of T92 steel were investigated. The irradiation hardening effect was observed in both the tempered and aged T92 samples. To eliminate the soft substrate effect, the critical indentation depth was determined using the ratio of the average hardness of irradiated and unirradiated samples at the same depth. Under the same irradiation conditions, the macroscopic hardness values of the aged T92 samples after irradiation were lower than those of the tempered samples. The irradiation hardening effect was more significant in the aged T92 due to the decreased dislocation density and the coarsened martensitic lath after long-term thermal aging.

9Cr铁素体/马氏体钢是有希望的先进第四代反应堆堆芯部件材料。在这些应用中，它们在热暴露下的长期微观结构稳定性以及对中子辐射的抵抗能力至关重要。使用回火（未时效）和长期热时效的T92样品来评估热时效和离子辐照对钢的显微组织和微机械性能的影响。回火和老化的样品均用3 MeV Fe ¹¹⁺辐照室温下离子浓度为0.25、0.50、1.00和5.00 dpa。利用纳米压痕技术，研究了T92钢的辐照硬化行为。在回火和老化的T92样品中均观察到了辐射硬化效果。为消除软性基材效应，使用在相同深度下受辐照和未辐照样品的平均硬度之比来确定临界压痕深度。在相同的辐照条件下，老化后的T92试样在辐照后的宏观硬度值低于回火试样。由于位错密度降低和长期热时效后马氏体板条变粗，T92时效中的辐照硬化效果更为显着。