Atomic displacement processes in irradiated metals

Irradiation of solids with energetic particles such as electrons, heavy ions and neutrons, results in the displacement of atoms from their lattice sites. In some cases the displaced atoms find metastable interstitial sites in the lattice, leaving vacant sites behind. In other cases, the atoms undergo switching processes with neighbors. No Frenkel defects are produced but atomic disorder is created. In this paper, the fundamental theory underlying these processes is presented. Topics include primary recoil spectra, spatial distributions of damage energy, defect production, and ion beam mixing. In addition to the traditional analytical theories of atomic collisions in solids, selected results of computer simulation are presented to elucidate the discussion and to introduce the latest developments in this field.