The influence of dislocations on neutron‐irradiation damage in molybdenum

The influence of various populations of cold‐work defect structures following heavy plastic deformation on the defect production during neutron irradiation of molybdenum at 330 K and on the annealing spectrum up to 1200 K has been investigated. It is observed that the presence of dislocations considerably enhances the defect retention. The annealing of this supplementary radiation damage is rather equally distributed over the whole recovery spectrum. From this radiation annealing of cold work stage III defects one could deduce an upper limit for the mean diameter d of the displacement cascade being equal to 40 lattice distances, which, in view of previous results, yields for d: 15 l.d < d < 40 l.d. The defect production plotted as a function of the pre‐irradiation annealing temperature yields a maximum, which can largely be accounted for by the radiation‐annealing of coldwork stage III defects.