Nano-indentation analysis was employed to investigate the mechanical response of heavy ion irradiated X-750 Ni-based superalloy in both solution-treated (ST) and precipitation-hardened (PH) conditions. Helium pre-implantation was carried out at 300 °C up to 5000 appm followed by Ni⁺-ion irradiation up to 1 dpa at room temperature or 400 °C. Cross-sectional TEM examination was used to characterize the microstructural evolution of the irradiated material and correlate this with nano-scale mechanical test results. Nano-hardness measurements after irradiation at 400 °C showed a similar trend of irradiation-induced hardening, for both ST and PH materials. In contrast, radiation at room temperature resulted in different mechanical responses, with hardening in the ST condition compared to softening in PH. The hardening behaviour was attributed to the creation of irradiation-induced defects including, cavities, Frank loops and small defect clusters; whereas, the γ′-precipitate instability (disordering/dissolution) in PH material resulted in the observed softening. The individual and combined contribution of each type of defects under irradiation hardening were estimated by employing three different obstacle models; results were verified by nano-indentation data for both ST and PH materials. In addition, the softening of the irradiated PH material which results from disordering and dissolution was separately calculated, allowing an estimate of the total yield strength change. TEM analysis of post-indentation microstructure revealed that un-irradiated X-750 deformed by homogenous dislocation motion; however, localized deformation in the form of nano-twins was the dominant deformation mechanism in irradiated X-750.

纳米压痕分析用于研究重离子辐照的X-750 Ni基高温合金在固溶处理（ST）和沉淀硬化（PH）条件下的机械响应。氦气的预先植入是在300°C至5000 appm的条件下进行的，然后进行Ni ⁺在室温或400°C下，离子辐照高达1 dpa。横截面TEM检查用于表征被辐照材料的微观结构演变，并将其与纳米级机械测试结果相关联。对于ST和PH材料，在400°C辐照后的纳米硬度测量结果显示出相似的辐照诱导硬化趋势。相反，室温下的辐射导致不同的机械响应，与ST的软化相比，在ST条件下变硬。硬化行为归因于辐照引起的缺陷的产生，包括空洞，弗兰克环和小的缺陷簇。相反，PH材料中的γ'沉淀不稳定性（无序/溶解）导致观察到的软化。通过采用三种不同的障碍物模型，估算了辐照硬化条件下每种类型缺陷的个体贡献和综合贡献。ST和PH材料的纳米压痕数据验证了结果。另外，分别计算了由无序和溶解引起的被辐射的PH材料的软化，从而可以估算出总屈服强度的变化。压痕后微观结构的TEM分析表明，未辐照的X-750因均匀的位错运动而变形。然而，纳米孪晶形式的局部变形是X-750辐照的主要变形机制。分别计算了由无序和溶解引起的被辐射PH材料的软化，从而可以估算出总屈服强度的变化。压痕后微观结构的TEM分析表明，未辐照的X-750因均匀的位错运动而变形。然而，纳米孪晶形式的局部变形是X-750辐照的主要变形机制。分别计算了由无序和溶解引起的被辐射PH材料的软化，从而可以估算出总屈服强度的变化。压痕后微观结构的TEM分析表明，未辐照的X-750因均匀的位错运动而变形。然而，纳米孪晶形式的局部变形是X-750辐照的主要变形机制。