The microstructural evolution of irradiation-induced point defects around the precipitates during in-situ 30 keV He+ irradiation was systematically investigated in Mo3Nb alloy using transmission electron microscopy (TEM) at various temperatures: room temperature (RT), 573 K, and 1073 K. The average size and volume number density of dislocation loops were obtain under the influence of irradiation temperature, fluence and different types (sizes and shapes) of precipitates. The irradiated defects showed distinct characteristics that correlated with the precipitate types. Dislocation loops of larger size and lower density were observed around the larger precipitates, which were also influenced by the precipitate morphology. Temperature had a great effect on defect migration, resulting in a decrease in loop density and an increase in loop size. Furthermore, the hardening effect attributed to irradiation-induced loops decreased with the increase of temperature and precipitate size. The dissolution of precipitates became increasingly pronounced with the increase of temperature, and irradiation could accelerate the process. At 573 K, the dissolution was only found in the large non-spherical precipitate, while at 1073 K, all the precipitates underwent dissolution. The annealing experiment conducted at 1073 K showed that the dissolution of large-sized precipitates would lead to the dispersion of small-sized precipitates, which was beneficial to increase the interfaces and potentially improve the radiation tolerance and mechanical properties of the alloy.

中文翻译：

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原位 He+ 照射和退火过程中沉淀物的演变及其对位错环的影响


使用透射电子显微镜 （TEM） 在不同温度下（室温 （RT）、573 K 和 1073 K）系统研究了原位 30 keV He+ 照射期间辐照诱导的析出物周围析出物周围点缺陷的微观结构演变。在照射温度、注量和不同类型（大小和形状）沉淀物的影响下，获得位错环的平均粒径和体积数密度。辐照缺陷显示出与沉淀物类型相关的独特特征。在较大的沉淀物周围观察到较大尺寸和较低密度的位错环，这也受到沉淀物形态的影响。温度对缺陷迁移有很大影响，导致环密度降低和环尺寸增加。此外，辐照诱导回路的硬化效应随着温度和沉淀物大小的增加而降低。随着温度的升高，沉淀物的溶解越来越明显，辐照可以加速这一过程。在 573 K 时，仅在较大的非球形沉淀物中发现溶解，而在 1073 K 时，所有沉淀物都发生了溶解。在 1073 K 下进行的退火实验表明，大尺寸析出物的溶解会导致小尺寸析出物的分散，这有利于增加界面，并可能提高合金的耐辐射性和机械性能。