Plastic deformation viewed as evolution of an active medium

The process of plastic flow in crystalline solids has been viewed as the evolution of an active medium in an open system far from thermodynamic equilibrium. The formation of lattice defects, the localization of strain and its variation in the different stages of flow are shown to be related to emergence and evolution of active media of definite types, the evolution of plastic flow involving propagation of different types of self-excited waves and formation of dissipative structures. The analogy with processes occurring in solids under deformation and with the emergence of structures in chemical and biological systems is discussed. Possible types of waves and observing conditions have been classified. 0 1997 Elsevier Science Ltd.