ON DENSITY EFFECTS IN POINT-DEFECT SOLUTIONS UNDER IRRADIATION .2. FORMATION OF INTERSTITIAL DISLOCATION LOOPS

The chemical potential approach, malting it possible for one to accoun t for density effects in supersaturated solution of point defects, is applied to consideration of interstitial loop formation kinetics iri m etals under homogeneous irradiation. Quasi-chemical rate equations are reformulated ill term of chemical potential, rather than in terms of concentrations of species involved in reactions, following a procedure known in the theory oi irreversible processes, The extension of rate equations is tested on a simpler model of bimolecular reactions, Then the density effect, such as radiation induced spontaneous clustering o f interstitials, is investigate in irradiated metals on the background of interstitial loop formation as described by conventional rate equa tion solution. The phenomenon, that reveals itself by spontaneous form ation of di-interstitials, would be expected to become noticeable at i rradiation temperatures about 0.25 to 0.3 of the absolute melting temp erature if the rate of defect generation is high enough. Wr a steady-s tart solution analyzed, the density effect brings about the higher num ber density uf forming interstitial loops with reduced mean dimensions if compared with conventional based consideration. Possibilities of e xperimental investigations of the proposed mechanism of interstitial l oop formation are discussed.