Swift heavy ion irradiation-induced microstructure modification of two delta-phase oxides: Sc4Zr3O12 and Lu4Zr3O12

Swift gold ions (185 MeV) were used to systematically investigate the radiation damage response of delta phase compounds Sc4Zr3O12 and Lu4Zr3O12 in the electronic energy loss regime. Ion irradiation-induced microstructural modifications were examined using X-ray diffraction (XRD) and transmission electron microscopy (TEM). XRD investigations indicate a phase transformation from ordered rhombohedral to disordered fluorite (O–D) in both compounds, with the Sc compound transforming at a higher ion fluence compared with the Lu compound. This result is consistent with our previous study on Sc4Zr3O12 and Lu4Zr3O12 under displacive radiation environment in which the nuclear energy loss is dominant. High resolution TEM revealed that individual ion tracks maintain crystalline structure, while the core region experiences an O–D phase transformation. TEM observations also suggest that for the doses in which the tracks overlap, the O–D phase transformation occurs across the entire ion range.