CONTRIBUTION OF INTERSTITIAL MIGRATION TO RADIATION-INDUCED SEGREGATION IN FCC BINARY-ALLOYS

The role of interstitials in the radiation-induced segregation (RIS) p rocess in a face-centered cubic (fee) binary alloy is investigated wit h a newly developed model. The model considers three types of intersti tial dumbbells, their diffusion and conversion via an interstitialcy m igration, recombination with a vacancy, and vacancy diffusion through the position exchange with a lattice atom. Analysis of RLS kinetics in the Cu-Au alloy is used to verify the model, and good agreement is ob tained with experimental measurements. The relationship is examined be tween the present model and the Wiedersich-Okamoto-Lam model (WOL mode l) in which the mixed dumbbell movement is neglected. Effective diffus ion coefficients are derived which incorporate the effect of the mixed dumbbell into the WOL model formulation.