The macroscopic shape change of a crystal cannot be adapted on the atomic level without changing the crystal structure. However, the crystal structure is conserved if crystallographic planes are displaced by integer multiples of the atomic spacing. This process is referred to as crystallographic slip. Crystallographic slip is always a shear deformation and can accommodate any macroscopic shape change.

Learning Outcomes for this Section

After completing this section, you should be able to:

• recall that dislocation glide is the mechanism of plastic deformation
• define the term slip system
• explain how dislocations interact with each other
• recall a relationship between dislocation density and strain hardening
• explain the influence of solute atoms and particles on strength
• explain the effect of temperature on strain hardening
• describe the mechanisms of dynamic recovery for edge and screw dislocations
• explain the effect of dynamic recovery on strain hardening

Pre-Requisites

Before starting, it is important that you are familiar with the following terms: crystal structure of metals; Miller indices for crystallographic planes and directions; diffusion of vacancies;