The dislocation bias during irradiation: Effects of climb motion and rate limitation

Abstract

The elastic-field model of a dislocation embedded in a lossy continuum is used to derive, analytically and rigorously, self-consistent expressions for the dislocation sink strength suitable for use in the chemical rate theory approach to the study of microstructural evolution during irradiation. These new expressions take proper account of the synergistic effects of the long-range elastic interaction between dislocations and point defects, dislocation climb motion, core rate limitation, and the influence of all types of sink involved. Numerical results are given for a range of dislocation densities, neutral sink strengths, temperatures, point-defect production rates and transfer lengths. It is found that making allowance for climb motion leaves the dislocation bias factor for interstitials essentially unchanged but increases that for vacancies, thus bringing a reduction of the dislocation net bias about. Making allowance for rate limitation, on the other hand, leads to a decrease of the dislocation bias factors for both types of point defect, with a consequential reduction or increase of the dislocation net bias itself.