ABSTRACT
We now enter the realm of plastic deformation of a solid material. Plastic deformation is not elastic: when the stresses that cause the deformation are removed, the deformation does not disappear. For crystalline materials, plastic deformation is associated with the motion of a particular kind of crystal lattice defect called a dislocation. Although this type of defect can be described up to a point by the continuum theory of solids, and will be so described in this chapter, more detailed understanding requires atomistic considerations.
