Self-organization reactions under irradiation: Toward the design of radiation-resistant materials

Irradiation can drive materials into non-equilibrium states, inducing phase transformations, and nanoscale structuration through self-organization. These nanostructures could impart radiation resistance by providing a large density of interfacial sites for point defect elimination, while at the same time improving mechanical properties. Two approaches are considered for alloys comprised of immiscible elements. In a first approach, for instance observed in Cu-Nb-W, nanoprecipitation of a highly immiscible solute (W in Cu) takes place during displacement cascade, providing a fractal-like template for the precipitation of a second and less immiscible solute (Nb). Atomistic kinetic Monte Carlo (KMC) simulations reveal that, under these conditions, nanoprecipitates can be completely resistant to thermal coarsening. In a second approach, the competition of ballistic mixing with thermal diffusion leads to self-organized nanoprecipitates with a finite steady-state lengthscale, which are thus coarsening resistant by design. KMC reveal that effective point-defect sinks can extend this nanopatterning to elevated temperatures.