CE 5310 Lecture Notes - Lecture 4: Work Hardening, Crystal Structure, Heaviside Step Function
Document Summary
Mechanisms of plastic deformation, strain-hardening, and bauschinger effect of. A dislocation is a linear or one-dimensional defect (or imperfection) around which some of the atoms are misaligned. All metals and alloys contain some dislocations that were introduced during solidification, during plastic deformation, and as a consequence of thermal stresses that result from rapid cooling. One type of dislocation is represented in figure 1. The atom positions around an edge dislocation; extra half-plane of atoms shown in perspective. Materials may experience two kinds of deformation: elastic and plastic. On a microscopic scale, plastic deformation corresponds to the net movement of large numbers of atoms in response to an applied stress. During this process, interatomic bonds must be ruptured and then re-formed. Plastic deformation corresponds to the motion of large numbers of dislocations. An edge dislocation moves in response to a shear stress applied in a direction perpendicular to its line; the mechanics of dislocation motion are represented in figure 2.
