Radiation Damage Behavior in Multiphase Ceramics (YSZ, Al2O3 and MgAl2O4) and the Effect of Heterointerfaces
- Author(s): Ohtaki, Kenta
- Advisor(s): Mecartney, Martha L
- et al.
Current technology ceramics for radiation environments rely on their intrinsic properties for damage tolerance, but the they can be further improved by designing the microstructure for use in applications for space, nuclear fission/fusion and nuclear waste environments. Interfaces are known to be sinks for point defects, which enhance radiation damage tolerance, and more disordered interfaces work better than clean interfaces. Heterointerfaces, or interfaces between dissimilar phases, are expected to have more disorder than grain boundaries in a single-phase system. In this study, radiation damage behavior of a multiphase ceramic material with heterointerfaces and submicron grains was systematically investigated and compared to single phase polycrystalline materials with grain boundaries. The multiphase composite survived a high fluence while single phase materials fractured. X-ray diffraction and transmission electron microscopy analysis showed more efficient point defect annihilation in the multiphase system than in the single-phase system. This work shows that high radiation damage tolerance can be achieved without complicated careful grain boundary modification or ultra nano grain fabrication, which is difficult to scale up and unreliable at elevated temperatures.