The effect of radiation upon diffusion in metals

Abstract Diffusion in metals proceeds via lattice defects, in particular point defects. Normally, these defects are provided as thermodynamic lattice disorders. Their concentration drops steeply with decreasing temperature. In “radiation enhanced diffusion” excess point defect concentrations are produced by incident radiation, e.g. high energy projectiles. Thereby not only the usual diffusion path is enhanced but also channels can be opened by way of defect species which are not available in normal thermally activated diffusion. Basic kinetic equations and their solutions are reviewed for homogeneous systems and in systems with extended sinks, producing local defect concentration gradients. New experimental developments in radiation enhanced short range ordering and clustering, precipitation and self-diffusion are examined. Material transport phenomena in surfaces are considered which appear greatly enhanced by irradiation.