辐照诱导的过饱和空位聚集形成空洞,进而引起的奥氏体不锈钢辐照肿胀现象会造成核反应堆内结构材料失效,危害反应堆安全.利用超高压电子显微镜,在300~500℃区间内,对SUS316L奥氏体不锈钢进行电子束辐照,原位观察辐照过程中空洞演变;辐照结束后,在透射电镜下观察空洞分布,并对空洞尺寸进行测量统计;对比研究不同温度下空洞演变的差异.结果表明:不同温度时电子辐照30 min后,可观察到点缺陷簇、位错环和空洞.其中450℃和500℃时,空洞尺寸最大,分别约为13.3 nm和14.5 nm.这是因为辐照温度升高会提高空位扩散能力,最终增大空洞尺寸.研究结果可为预测不同工作温度下奥氏体不锈钢中辐照肿胀提供实验依据.%Void swelling in austenitic stainless steel degrades the properties of materials used in reactors due to the accumulation behavior of radiation-introduced excess vacancies, which brings a serious threat to the safety of reactor. In this paper, electron beam irradiations were conducted by high voltage electron microscope in a temperatures range of 300~500 ℃, and insitu observation of the void evolution was carried out during irradiations. Void distributions were observed and void sizes were measured using transmission electron microscope after irradiations. The differences among the void evolution under different irradiation temperatures were investigated. The results show that large amounts of point defect clusters, loops, and voids can be observed under electron beam irradiations of different temperatures. Voids formed at 450 ℃and 500 ℃ are the largest, with a size of 13.3 nm and 14.5 nm, respectively. As the irradiation temperature increases, the diffusion of excess vacancies is enhanced, which leads to the enlargement of void size. These results are expected to provide a reference for forecasting the void swelling in austenitic stainless steel under different irradiation temperatures.
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