Reaction-transport dynamics and dislocation patterns in deformed materials

Abstract

Dislocation patterns arise in a large variety of situations where crystalline materials are submitted to mechanical constraints such as cyclic or monotonous loadings. It may be shown that, under the combined effect of defect motion and interactions, uniform dislocation distribution may become unstable versus spatial modulations leading to the formation of various kinds of patterns going from cellular to wall or labyrinth structures. The formation of the wall structure of persistent slip bands in fatigued metals is discussed and analyzed in the framework of nonlinear dynamics of the reaction-transport type. The important of the concepts of instability and self-organization in the fundamental understanding of materials instabilities and defect microstructures is emphasized.