Real Materials

Dislocations

· Dislocations are Line defects - - One dimensional defects that control the mechanical properties of bulk materials. A typical material has a dislocation density of about 10⁸ m/m³

· The straight Edge dislocation illustrated is associated with a local extra half-plane of atoms in the crystal.
· The dislocation is characterized by two parameters: the Burgers vector, b, and the Line vector, t.
· For the Edge dislocation, b is normal to t.
· The plane defined by (b, t) is the slip plane on which the dislocation can move during sample deformation.

From: Callister,
"Materials Science and Engineering,"
Wiley (1997)