Gamma-phase lithium aluminate (gamma-LiAlO2) is a breeder material for tritium, a necessary substance for strategic stockpile and fusion power systems. A fundamental study of structural evolution and tritium diffusion in gamma-LiAlO2 under displacive irradiation is needed to fully assess the material performance. This study utilizes ion implantation of protium (surrogate for tritium) and helium in gamma-LiAlO2 single crystals at elevated temperatures to emulate the irradiation effects. The results show that at 573 K there are two distinct disorder saturation stages to 1 dpa without full amorphization; overlapping implantation of H2+ and He+ ions suggests possible formation of gas bubbles. For irradiation to 1E21 H+/m2 (0.36 dpa at peak) at 773 K, amorphization occurs at surface with H diffusion and dramatic Li loss; the microstructure contains bubbles and cubic LiAl5O8 precipitates with sizes up to 200 nm or larger. In addition, significant H diffusion and release are observed during thermal annealing.
Revised: July 25, 2020 |
Published: January 18, 2017
Citation
Jiang W., J. Zhang, L. Kovarik, Z. Zhu, L. Price, J. Gigax, and E. Castanon, et al. 2017.Irradiation effects and hydrogen behavior in H2+ and He+ implanted gamma-LiAlO2 single crystals.Journal of Nuclear Materials 484.PNNL-SA-114795.doi:10.1016/j.jnucmat.2016.03.014