Grundzüge der Deformationsprozesse in Metallen

The physical principles of our present understanding of the elastic, the anelastic, and the plastic deformation of metals are discussed. The following specific cases are considered in details.

1. Elastic deformation due to one of the following processes. Energy elasticity, vibrational entropy elasticity, anomalies in the elastic behaviour resulting from lattice instability or ferromagnetism. This behaviour is compared with the entropy and energy elasticity of polymers.
2. Anelastic deformation due to one of the following mechanisms. Difussion of solute atoms and/or point defects, dislocation relaxation, dislocation resonance interaction between dislocations and other lattice defects, migration of grain boundaries, phase boundaries or domain walls.
3. Plastic deformation of pure metals by cooperative shear, dislocation motion, mechanical twinning, martensitic transformations and by diffusion. The effect of alloying on these processes is discussed in the case of solid solutions, ordered alloys and precipitation hardened materials. The dominant deformation modes of polymers are different from those of metals because metals are formed by atoms with relatively isotropic interatomic forces, whereas polymers generally consist of long chains characterized by a strong anisotropy in chemical bonding. This difference makes the deformation stress of polymers and metals depend differently on temperature, pressure, and deformation rate. An other characteristic difference between the deformation of polymers and metals is that metals deform plastically, whereas a large fraction of the so-called plastic deformation of polymers is really anelastic.