| Abstract Scope |
Irradiation by energetic particles is well known to produce damage (e.g., disorder) in crystalline solids. Surprisingly, irradiation has also been observed to induce ordering, including nanoscale precipitation, domains of aligned dislocation loops, and void and gas-bubble superlattices, offering the opportunities of modifying materials microstructure for desired properties, provided that the behind mechanisms are understood. This talk focuses on nanoscale void and gas-bubble superlattices that form in metals under irradiation. We will first show a rate-theory based instability theory that can predict both the superlattice parameter and structure. Following that, the impact of irradiation condition and material properties on superlattice properties, including lattice parameter, crystal structure, and degree of ordering, will be elucidated by both theoretical analysis and mesoscale simulations. An equivalency between irradiation temperature and dose rate is identified for promoting superlattice formation with optimal ordering. Possible superlattice formation in nanocrystalline materials and nanoparticles is also studied by simulations. |