Dislocations in irradiated crystals. Chapter 12

Under irradiation, the dislocation structure of crystals undergoes quantitative as well as qualitative changes. The magnitude of the dislocation density may change several orders of magnitude, increasing or decreasing depending on the magnitude of the original dislocation density. It is well-known that fast-neutron irradiation decreases the dislocation density in cold-worked austenitic steels and increases the dislocation density in annealed samples of the same alloy. After irradiation by a flux of about 1022 neutrons cm-2, the dislocation density reaches the same constant value in both cases. Since uniform irradiation does not produce macroscopic stresses that could cause dislocation glide, one must assume that the dislocation rearrangements taking place during irradiation are exclusively due to dislocation climb, dislocation-dislocation annihilation and the nucleation of new loops, all of which are processes that can be driven by a supersaturated solid solution of point defects. (author). 94 refs., 6 figs