Question

Partial dislocations are associated with:

• A. FCC metals
• B. BCC metals
• C. HCP metals
• D. Ceramics only

Hint:

Partial dislocations are typical in FCC metals, where perfect dislocations can split into two Shockley partials separated by a stacking fault — this aids ductility.

Answer 1

The Correct Option is A

Partial dislocations are dislocations in a crystal lattice where the Burgers vector is smaller than that of a full dislocation. They commonly occur in face-centered cubic (FCC) metals due to the structure’s ability to split a perfect dislocation into two or more partial dislocations.
In FCC metals, a perfect dislocation can dissociate into two Shockley partial dislocations, separated by a stacking fault. This phenomenon is a key mechanism for plastic deformation and influences material properties such as ductility and work hardening.
- BCC metals typically exhibit non-planar core structures and do not favor partial dislocations.
- HCP metals have limited slip systems and also do not commonly exhibit partial dislocations.
- Ceramics are typically brittle and do not rely on dislocation slip as a major deformation mechanism.