Analysis of deformation structures in FCC materials using EBSD and TEM techniques

Abstract

In a large number of industrially important metals and alloys, a fraction of the dislocations generated during deformation remain trapped and arranged into well-defined dislocation boundaries (Bay et al. 1992; Hansen and Juul Jensen 1999; Hughes and Hansen 2000; Li et al. 2004). Extensive investigations using the transmission electron microscope have established that these dislocation boundaries separate volumes of different crystal orientations, and that two classes of dislocation boundaries can be defined (Liu et al. 1998; Hansen 2001). Individual cells are delineated by boundaries referred to as incidental dislocation boundaries (IDBs). These dislocation cells are grouped into cell-blocks, delineated by long planar dislocation boundaries, referred to either as extended planar boundaries or geometrically necessary boundaries. Two of the key quantitative parameters for describing the deformed microstructure are therefore the misorientation angle across each boundary, and the spacing between adjacent dislocation boundaries. This description of the deformed microstructure has proved very useful both in providing information to understand the underlying processes taking place during plastic deformation, and in providing quantitative data that can be used to assess both the mechanical properties and the thermal stability of a deformed sample. © Springer Science+Business Media, LLC 2009. All rights reserved.