Heavy ion irradiation-induced microstructural evolution in pyrochlore Lu2Ti2O7 at room temperature and 723 K

Pyrochlore Lu2Ti2O7 pellets were irradiated by heavy ions at RT and 723 K.At RT irradiation, ~75% of amorphization was achieved.The nano-crystals were formed in the damage layer at RT irradiation.The formed nano-crystals enhanced the radiation tolerance of Lu2Ti2O7.A pyrochlore to fluorite phase transformation was observed at 723 K irradiation.

Polycrystalline pyrochlore Lu2Ti2O7 pellets were irradiated with 600 keV Kr3+ at room temperature and 723 K to a fluence of 4×1015 ions/cm2, corresponding to an average ballistic damage dose of 10 displacements per atom in the peak damage region. Irradiation-induced microstructural evolution was examined by grazing incidence X-ray diffraction, and cross-sectional transmission electron microscopy. Incomplete amorphization was observed in the sample irradiated at room temperature due to the formation of nano-crystal which has the identical structure of pyrochlore, and the formation of nano-crystal is attributed to the mechanism of epitaxial recrystallization. However, an ordered pyrochlore phase to a swelling disordered fluorite phase transformation is occurred for the Lu2Ti2O7 sample irradiated at 723 K, which is due to the disordering of metal cations and anion vacancies.

Graphical AbstractPolycrystalline pyrochlore Lu2Ti2O7 pellets were irradiated with 600 keV Kr3+ to a fluence of 4×1015 ions/cm2 at room temperature and 723 K, Incomplete amorphization was observed in the sample irradiated at room temperature due to the formation of nano-crystal. However, an ordered pyrochlore phase to a swelling disordered fluorite phase transformation is occurred for the Lu2Ti2O7 sample irradiated at 723 K, which is due to the disordering of metal cations and anion vacancies.Figure optionsDownload full-size imageDownload as PowerPoint slide