Structural evolution of Lu(2-x)Ce(x)Ti(2)O(7)pyrochlores under 400 keV Ne irradiation
Structural evolution of Lu(2-x)Ce(x)Ti(2)O(7)pyrochlores under 400 keV Ne irradiation
复制标题
400 keV Ne辐照下Lu(2-x)Ce(x)Ti(2)O(7)烧绿石的结构演化
DOI：
10.1111/jace.17290
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发表时间：
2020
影响因子：
3.9
通讯作者：
Li Yuhong
中科院分区：
文献类型：
--
作者：
Xia Yue;Yang Dongyan;Chen Chien-Hung;Hao Yan;Ewing Rodney C.;Li Yuhong
用能量为400 keV、注量（剂量）高达5 × 1015 ions/cm ~ 2（1.875 dpa）的Ne ~（2+）对Lu 2-xCexTi_2O_7（LCTO）高温超导体进行辐照。结合掠入射角X射线衍射（GIXRD）和透射电子显微镜（TEM）研究了详细的损伤过程。在1 × 1014 ions/cm ~ 2（0.037 dpa）的注量下溶胀2%后，初始溶胀的LCTO烧绿石在5 × 1014 ions/cm ~ 2（0.185 dpa）的注量下形成了无序的萤石相和纳米晶烧绿石相。在较高的能量密度下，当剂量达到1 × 1015 ions/cm 2（0.371 dpa）时，萤石相随着非晶畴体积的增加而减少，而纳米焦绿石相持续存在。在5 × 1015 ions/cm ~ 2（1.854dpa）的最高能量密度下，焦绿石纳米晶的非晶化率降低，结晶度提高，超晶格衍射峰强度增加。相变和再结晶可以通过辐射诱导的膨胀烧绿石微晶中的应变释放来解释。的损伤过程的演变主要是驱动的差异，在吉布斯自由能的萤石相相比，烧绿石相作为晶粒尺寸的函数。我们已经证明，离子束技术可以用来操纵相稳定性和微晶尺寸的烧绿石。这些结果为定制高温超导体的机械强度和对极端辐射环境的响应提供了基础。
Lu2‐xCexTi2O7(LCTO) pyrochlores were irradiated by 400 keV Ne2+with fluences (dose) of up to 5 × 1015ions/cm2(1.875 dpa). The detailed damage process was investigated by combining grazing incident angle X‐ray diffraction (GIXRD) and transmission electron microscopy (TEM). Subsequent to the 2% volume swelling at a fluence of 1 × 1014ions/cm2(0.037 dpa), the initially swollen LCTO pyrochlore formed both a disordered fluorite phase and a nanocrystalline pyrochlore phase at a fluence of 5 × 1014ions/cm2(0.185 dpa). At higher fluences, the fluorite phase diminished as amorphous domains increased in volume when the dose reached a fluence of 1 × 1015ions/cm2(0.371 dpa), while the nanocrystalline pyrochlore phase persisted. At the highest fluence of 5 × 1015ions/cm2(1.854 dpa), the amorphous fraction decreased, meanwhile the degree of crystallinity of nanocrystalline pyrochlore phase was enhanced, as evidenced by the increased intensity of superlattice diffraction maxima. The phase transformation and recrystallization can be explained by the release of strain in irradiation‐induced swollen pyrochlore crystallites. The evolution of the damage process is mainly driven by the differences in the Gibb's free energies of fluorite phase as compared with the pyrochlore phase as a function of grain size. We have demonstrated that ion beam techniques can be used to manipulate the phase stability and crystallite size of pyrochlore. These results provide the basis for tailoring the mechanical strength and response of pyrochlores to extreme radiation environments.