Lei Penghui, Ran Guang, Liu Chenwei, Ye Chao, Lv Dong, Lin Jianxin, Wu Yizhen, Xu Jiangkun
College of Energy, Xiamen University, Xiamen 361102, Fujian, China.
Materials (Basel). 2017 Apr 22;10(4):437. doi: 10.3390/ma10040437.
The microstructure evolution of Zr-1.1Nb-1.51Fe-0.26Cu-0.72Ni zirconium alloy, irradiated by 800 keV Kr ions at 585 K using the IVEM-Tandem Facility at Argonne National Laboratory, was observed by in situ transmission electron microscopy. A number of β-Nb precipitates with a body-centered cubic (BCC) structure were distributed in the as-received zirconium alloy with micrometer-size grains. Kr ion irradiation induced the growth of β-Nb precipitates, which could be attributed to the segregation of the dissolved niobium atoms in the zirconium lattice and the migration to the existing precipitates. The size of precipitates was increased with increasing Kr ion fluence. During Kr iron irradiation, the zirconium crystals without Nb precipitates tended to transform to the nanocrystals, which was not observed in the zirconium crystals with Nb nanoparticles. The existing Nb nanoparticles were the key factor that constrained the nanocrystallization of zirconium crystals. The thickness of the formed Zr-nanocrystal layer was about 300 nm, which was consistent with the depth of Kr iron irradiation. The mechanism of the precipitate growth and the formation of zirconium nanocrystal was analyzed and discussed.
利用阿贡国家实验室的IVEM串联加速器装置，在585 K下用800 keV的氪离子辐照Zr-1.1Nb-1.51Fe-0.26Cu-0.72Ni锆合金，通过原位透射电子显微镜观察了其微观结构演变。在初始的具有微米尺寸晶粒的锆合金中分布着许多体心立方（BCC）结构的β-Nb析出相。氪离子辐照导致β-Nb析出相生长，这可归因于溶解在锆晶格中的铌原子的偏析以及向现有析出相的迁移。析出相的尺寸随着氪离子注量的增加而增大。在氪离子辐照过程中，没有Nb析出相的锆晶体倾向于转变为纳米晶体，而在含有Nb纳米颗粒的锆晶体中未观察到这种现象。现有的Nb纳米颗粒是限制锆晶体纳米晶化的关键因素。形成的Zr纳米晶层厚度约为300 nm，这与氪离子辐照深度一致。分析并讨论了析出相生长和锆纳米晶形成的机制。
