Irradiation of solid materials with energetic neutrons or charged particles can lead to profound changes in defect structure, microcomposition, and macroscopic properties. Such changes occur by atomic and microstructural mechanisms, some of which are familiar in "classical" physical metallurgy and materials science. However, other cases appear to be unique to irradiation. Irradiation has considerably broadened and indeed provided an entirely new dimension in materials science, since the energetic displacement of atoms potentially reaches to every property or process. The initial damaging events leading to the creation of point defects are generally complete in times of order 10−11 s. Subsequent changes in structure, composition, and properties take place in a span of much longer time scales corresponding to interstitial and vacancy diffusion, clustering, solute segregation, and precipitation. An extensive theoretical framework has been developed to understand the kinetics of these processes. Emphasis has been placed on both steady cumulative processes and on fluctuations, and on the appropriate application of stochastic and deterministic descriptions. Parallel and interactive experimental activities for both applied and basic programs over the past two decades have increased the level of phenomenological knowledge enormously. Much of the work has emphasized either high-dose phenomena such as irradiation-induced swelling, creep, embrittlement, phase instability, and solute segregation relevant to materials applications, or the properties, structures, and interactions of defects, which underlie more fundamental issues.
The controlled synthesis of complex hollow nanostructures and prospective applications
