Radiation Processes in Crystal Solid Solutions

The main kinds, properties and radiation units of measure are considered. The data on the path of the microparticles in metals and air are presented. The crystal structure of the metals and alkali halides is considered. The models of various kinds of structural defects (point, linear, volume) in crystal lattice are discussed.

Models and mechanisms of intrinsic radiation defect formation in the metals and alkali-halide crystals are considered. The effect of irradiation conditions (temperature, absorbed dose, etc.) on the formation of the primary and secondary defects, fomation of the aggregate radiation defects (voids), and affection of heat treatment on the properties of irradiated metals are discussed herein. It is noted that low radiation resistance of alkali halide crystals is connected to the under-threshold mechanism of defect formation.

The models and thermal stability of the impurity radiation defects in the metals and alkali halides are reviewed. Due to the ionic lattice structure and presence of two sublattices in alkali halides, the formation of much larger number of types of impurity radiation defects than in metals is possible. The most important in the radiation processes are the complexes of self-interstitial-impurity and vacancy-impurity.

The effect of impurity atoms on the efficiency of formation and accumulation of radiation defects in the metals and alkali halide crystals is considered. Interaction of impurities with radiation defects can both promote stabilization of the structural disorder, and suppress the radiation-defect formation. Especially the complex processes take place in the irradiated alkali halide crystals, where a wide variety of the radiation-induced defects is possible.

Some experimental data on the radiation-stimulated diffusion in metals and alkali halides are presented. The diffusion mechanisms in the crystal solids under irradiation and the effect of temperature irradiation on the diffusion are discussed. It is noted that the super-equilibrium point defects play a major role in the radiation-stimulated diffusion.

The experimental data of the effect of irradiation on the decomposition of alloys and doped alkali halide crystals are presented. Depending on the composition of the solid solution and other conditions, the irradiation can both accelerate and induce the decomposition. The mechanisms and some features of the decomposition of solid solution under irradiation are discussed.

The factors affecting the stability of solid solutions under irradiation are considered. One of these factors is the radiation-induced change of solubility. The models describing the radiation-induced decomposition of the solid solution for the different concentrations of impurities and irradiation conditions are discussed.

The experimental data and models of radiation-induced segregation are presented. The mechanism and efficiency of the radiation-induced segregation depend on several factors: the irradiation temperature, the concentration and size of atoms of impurity, the presence of additional impurity, etc. The majority of models which describe the radiation-induced segregation, include a system of kinetic equations for the various kinds of point defects and alloy atoms. The models differ from each other in a set of the types of defects and calculation parameters.

The radiation-induced disordering and amorphization are considered. These phenomena are not connected with the fluxes of impurity atoms and radiation defects. The criteria for radiation amorphization which is connected with the degree of mixing of the alloy components, are discussed.