MASS-TRANSPORT PROCESSES INITIATED IN MULTIELEMENTAL SOLIDS AFFECTED BY ION-BEAM IRRADIATION

The experimentally observed non-monotonous time dependence of the surf ace composition initiated by sharp changes in parameters of ion irradi ation of multielemental materials are explained on the basis of consid eration of preferential sputtering and component interdiffusion. The d riving force of the component interdiffusion is the preferential sputt ering which forms concentration gradients of components in the near-su rface layer. The influence of the target temperature on the kinetics o f the surface composition is explained including the process of the ra diation activated temperature gradient diffusion (RATGD), which is ini tiated by the nonuniform distribution of phonon energy of atoms across the subsurface layer which matches the distribution of nuclear energy losses of penetrating ions. The conditions when the process of RATGD affects the distribution profile of constituents in the altered layer and the steady-state surface composition are considered. In order to s tudy the changes of component composition produced by RATGD the proces ses of segregation, which, generally, cannot be neglected, are not inc luded into model.