Self-organization in materials subjected to irradiation and plastic deformation

Materials are commonly subjected to external forcing, for instance plastic deformation during fabrication and shaping, and irradiation during service life in nuclear reactors. While such nonequilibrium forcing can introduce detrimental evolution of material properties, it also creates opportunities for the dynamical stabilization of novel microstructures via self-organization. In particular, ion irradiation and plastic deformation can result in the stabilization of intragranular nanoprecipitates. These intragranular nanoprecipitates can impart radiation resistance by providing a large and stable density of interfacial sites for point defect elimination, while at the same time improving mechanical properties. We use phase field modeling of generic alloys subjected to irradiation for mapping out the domains of stability of various competing steady states, which are then organized into steady-state phase diagrams. We show that the evolution of these alloys can be seen as driven by effective free energies, thus allowing for a direct rationalization of those steady-state phase diagrams. We show that a novel definition of interface energy is needed when these alloys self-organize into nanoscale patterns. An additional intriguing result is that not only phases but also microstructures can coexist in driven systems, suggesting that self-organization, and self-adaptation, can take place at a global scale.