PNNL

Abstract

Void lattices in irradiated metals were first observed about 30 years ago [1], and while they have been the subject of many theoretical and experimental studies since then, no definitive theory of void lattice formation exists. Crowdion clusters having the property of three-dimensional diffusion in the material along paths consisting of segments of one-dimensional random walks are central to the Production Bias Model of void swelling [2], which has been shown to be quite successful in describing many aspects of microstructure evolution under cascade-producing irradiation. The rationale for the present investigation is that if a theory can explain void swelling, then it should also be compatible with the formation of void lattices. Thus, a key element of the Production Bias Model, the one-dimensional migration of crowdion clusters with occasional Burgers vector changes, was examined as a necessary condition for the formation of a void lattice.