Chemical imaging and diffusion of hydrogen and lithium in lithium aluminate

Abstract Tritium ( 3 H) must be replenished for strategic stockpile and fusion reactors. 6 Li-enriched γ-LiAlO 2 pellets have been used for 3 H production by thermal neutron irradiation. A fundamental study of 3 H and 6 Li diffusion processes in irradiated γ-LiAlO 2 pellets is needed to assess and predict the long-term material performance. This study focuses on identifying the trapping sites and diffusion pathways of 1 H (a surrogate for 3 H) and Li atoms in polycrystalline γ-LiAlO 2 pellets irradiated with both 4 He + and 1 H 2 + ions. A combination of STEM-EELS, Nano-SIMS and APT is employed for chemical imaging at nanoscale resolution. There is direct evidence for preferred Li diffusion pathways along grain boundaries. Isolated voids are identified as possible Li trapping sites in the irradiated γ-LiAlO 2 pellets. Possible lithium hydrides and/or hydrates are precipitated on the surface of the irradiated pellets. This study improves our understanding of H and Li diffusion processes and provides data for modelling and simulation to predict material performance during neutron irradiation of γ-LiAlO 2 pellets.