ORDERING AND DISORDERING OF SOLID-SOLUTIONS UNDER IRRADIATION

A review is presented of the long-range ordering and disordering of solid solutions under irradiation. The study is based upon research papers which have been published over the past thirty years, and focuses on the experimental evidence for the phenomena and the underlying mechanisms. Also, the work discusses the crystalline-to-amorphous transformation which occurs in certain systems. It is concluded that ordering and disordering occur under cascade-producing Irradiation (fastneutrons and heavy-ions) and under non-cascade-producing irradiation (energetic electrons); that the degree of long-range order decreases exponentially with increasing fluence; that cascade-producing irradiation is more effective than non-cascadeproducing irradiation in creating disorder; that irradiation at intermediate temperatures leads to an intermediate degree of order; that the thermally activated migration of vacancies is the dominant mechanism underlying irradiation-induced ordering; and that thermal spikes, replacement collision sequences and random vacancy/interstitial recombinations are probable disordering mechanisms of which the relative importance varies with the nature of the irradiation. © 1979.