Determination of sink concentrations in ion irradiated nickel and copper by diffusion measurements

Abstract

Diffusion coefficients of nickel in nickel and in copper were measured after 300 keV self-ion irradiation at temperatures between 293 and 1000 K with dose rates between 10−5and 3 × 10−2 dpa/s and doses between 0.2 and 102 dpa. The results were analyzed by means of a rate equation model characterizing the sink strength of the substructure by an effective sink concentration. At lower temperatures, sink concentrations (in terms of atomic units) of 2 × 10−6 in nickel and 2 × 10−5 in copper were deduced. Above 850 K. in nickel and 500 K in copper these sink concentrations decreased considerably. In nickel the effective sink concentration became stationary for doses greater than 0.2 dpa. The present results indicate a higher effective sink concentration than has been deduced so far from electron microscopy investigations.