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Role of interfaces in damage process of irradiated lithium aluminate nanocrystals
Author(s) -
Setyawan Wahyu,
Senor David J.,
Devanathan Ram
Publication year - 2019
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.16051
Subject(s) - grain boundary , materials science , nanocrystalline material , amorphous solid , nanocrystal , annealing (glass) , chemical physics , ion , irradiation , crystallography , crystallographic defect , grain size , nanotechnology , composite material , microstructure , chemistry , physics , organic chemistry , nuclear physics
Molecular dynamics simulations were performed to understand the differences in the response of single crystal and nanocrystalline γ‐LiAlO 2 to energy deposition by 10 keV Li recoils. The simulations are performed at 573 K and focus on the damage production in the absence of thermal annealing. The grain boundaries in the nanocrystals are found to be amorphous. Analyses of the fate of the beam ions show that the amorphous grain boundaries and differently oriented nanograins increase the number of backscattered ions and decrease the number of transmitted ions. Damaged regions protruding from the grain boundaries provide a direct evidence of the role of the grain boundaries as scattering centers in collision cascades. The simulations show that the defect density produced in the nanocrystals is about twice that in the single crystals. In both samples, Li defects account for 70% of the defects, demonstrating that LiO 4 tetrahedra are much more susceptible to damage than AlO 4 tetrahedra. Furthermore, Li defects occur preferentially near grain boundaries. Diffusion simulations confirm the limited thermal diffusion of defects at 573 K, effectively separating the damage production from thermal annealing in the irradiation simulations. Nevertheless, the mean square displacements of grain‐boundary defects are found to be larger than lattice defects and surface defects.