Abstract
Nanoparticles, due to their small size and radiation absorption property, are widely used in nano nuclear nanotechnology as well as radiation environment. Radiation-induced defects could negatively affect mechanical properties, potentially leading to accidents. In this study, the molecular dynamics (MD) method, as a powerful atomic-level simulation tool, is applied to investigate and characterize the formation and evolution of point defects in irradiated Fe nanoparticle (NP) and core-shell Ti-TiO2 NP by using a recent updated many-body interatomic potential. MD especially helps us gain access to length and time scales that are not accessible experimentally and learn more about the multi-scale phenomena that occur during the irradiation of nanomaterials. Computer simulations provide information at the microscopic level, acting as a bridge to the experimental observations and giving insights into processes that take place at small time and length scales. The increasing computer capabilities in combination with recently developed scalable codes, and the availability of realistic potentials set the stage to perform large scale simulations, approaching phenomena that take place at the atomistic and mesoscopic scale in a more realistic way. This dissertation has focused on understanding the atomic-level mechanism of irradiation damages and defect formations in Fe nanoparticle (NP) and core-shell Ti-TiO2 NP. To test the NPs compatibility for several neutron energy and temperature stability, a series of MD simulations have been done for Fe NP and core-shell Ti-TiO2 NP. The results from the simulation provide the defect orientation on NP after irradiation and can be used to predict the experimental results.