This article may be too technical for most readers to understand.(April 2021)
In materials science, a partial dislocation is a decomposed form of dislocation that occurs within a crystalline material. An extended dislocation is a dislocation that has dissociated into a pair of partial dislocations. The vector sum of the Burgers vectors of the partial dislocations is the Burgers vector of the extended dislocation.
A dislocation will decompose into partial dislocations if the energy state of the sum of the partials is less than the energy state of the original dislocation. This is summarized by Frank's Energy Criterion:
Shockley partial dislocations
Shockley partial dislocations generally refer to a pair of dislocations which can lead to the presence of stacking faults. This pair of partial dislocations can enable dislocation motion by allowing an alternate path for atomic motion.
In FCC systems, an example of Shockley decomposition is:
Which is energetically favorable:
The components of the Shockley Partials must add up to the original vector that is being decomposed:
Frank partial dislocations
Frank partial dislocations are sessile (immobile), but can move by diffusion of atoms. In FCC systems, Frank partials are given by:
- Meyers and Chawla. (1999) Mechanical Behaviors of Materials. Prentice Hall, Inc. 217.
- "5.4.2 Dislocation Reactions Involving Partial Dislocations". Tf.uni-kiel.de. Retrieved 2013-09-21.
- W.D. Nix. "Partial Dislocation Tutorial for FCC Metals" (PDF). Imechanica.org. Retrieved 2013-09-21.
- Meyers and Chawla. (1999) Mechanical Behaviors of Materials. Prentice Hall, Inc. 218-219.