Metalworking

The shaping of metals and alloys by cold work is an ancient art that has largely been developed empirically. In recent years, understanding has grown of the parameters governing plastic deformation, and it has become possible to control mechanical properties with a very high degree of precision. Understanding the relationship between the working conditions and the microstructural evolution on one side, and the relationship between microstructure and mechanical properties on the other is the subject of this chapter. We begin by summarizing the various metalworking processes that are available, comparing them on the basis of the nature and magnitudes of the strains that can be imparted.We then examine the nature and role of dislocations in plastic deformation. A section follows on the experimental techniques that are available for analyzing different aspects of the deformation microstructure. The development of deformation microstructures is then discussed in detail, together with models and hypotheses for their formation and evolution. In the following section, the way in which the microstructure leads to strengthening is examined, leading to a presentation of the different models and equations for the relationship between structural parameters and mechanical properties. Finally, some future trends are identified