The behaviour of incidental dislocation boundaries and geometrically necessary boundaries during warm tensile deformation of aluminium

Abstract

It has been well established experimentally that, during plastic deformation of a polycrystal, individual grains are gradually subdivided into mutually misoriented regions separated by dislocation rotation boundaries. At small strains, slightly misoriented ordinary dislocation cells are created that are characterized by tangled dislocation boundaries. According to the theory of low-energy dislocation structures (LEDS), these boundaries result from the statistical mutual trapping of glide dislocations into low-energy configurations and are, therefore, termed incidental dislocation boundaries (IDBs). With increasing strain, planar dislocation walls called geometrically necessary boundaries (GNBs) develop gradually on the background of ordinary dislocation cells and, thus, divide the grain into cell blocks (CBs) that contain from one to several cells.