What is the Difference Between Edge and Screw Dislocation?
🆚 Go to Comparative Table 🆚Edge and screw dislocations are both types of defects in crystal structures, commonly found in materials science and metallurgy. The main differences between them are:
- Burgers Vector: An edge dislocation has its Burgers vector perpendicular to the dislocation line, while a screw dislocation has its Burgers vector parallel to the dislocation line.
- Dislocation Line: Edge dislocations can be visualized as an extra half-plane of atoms, whereas screw dislocations involve the movement of atoms in a helical arrangement around the core.
- Movement: When a dislocation moves under an applied shear stress, the individual atoms in an edge dislocation move in directions parallel to the Burgers vector, causing the dislocation to move in a direction perpendicular to the dislocation line. In contrast, a screw dislocation moves in a direction perpendicular to the Burgers vector.
- Glide Plane: Edge dislocations can glide in any plane, while screw dislocations can also glide in any plane.
In summary, edge dislocations are easier to visualize and involve the movement of individual atoms perpendicular to the dislocation line, while screw dislocations involve a more complex helical arrangement of atoms and move in a direction perpendicular to the Burgers vector.
Comparative Table: Edge vs Screw Dislocation
The main difference between edge and screw dislocations lies in their crystallographic defects and the way they respond to stress. Here is a table summarizing the differences between edge and screw dislocations:
| Feature | Edge Dislocation | Screw Dislocation |
|---|---|---|
| Definition | Edge dislocation occurs when an extra half-plane of atoms exists in the middle of a crystal lattice. | Screw dislocation occurs when the atomic planes are distorted in a spiral or helical manner. |
| Burger's Vector | A vector that describes the shift of the lattice planes in a dislocation. Edge dislocation has a non-zero Burger's vector, indicating a shear stress component. | The Burger's vector is zero for screw dislocations, indicating no shear stress component. |
| Stress Response | When stress is applied, the dislocation area moves parallel to the direction of stress. | Stress response is relatively less complex compared to edge dislocation, and the dislocation area moves perpendicular to the direction of stress. |
| Mobility | Edge dislocation velocity remains constant. | Screw dislocation mobility increases with increasing temperature. |
| Glide Planes | Edge dislocations can glide in any plane. | Screw dislocations can also glide in any plane. |
In summary, edge dislocations are characterized by an extra half-plane of atoms and a shear stress component, while screw dislocations are characterized by a spiral or helical distortion of atomic planes and no shear stress component. The response to stress and mobility of these dislocations also differ, with edge dislocations moving parallel to the direction of stress and screw dislocations moving perpendicular to the direction of stress.
- Dislocation Creep vs Diffusion Creep
- Bolt vs Screw
- Cortical vs Cancellous Screw
- Dissolution vs Disintegration
- Friction vs Shear
- Deformation vs Strain
- Distance vs Displacement
- Sprain vs Fracture
- Fusion vs Solidification
- Spondylosis vs Spondylolisthesis
- Elastic vs Plastic Deformation
- Single Displacement vs Double Displacement Reaction
- Origin vs Insertion
- Dipole Dipole vs Dispersion
- Clips vs Spacers
- Schottky Defect vs Frenkel Defect
- Cleavage vs Fracture
- Torque vs Torsion
- Anterolisthesis vs Spondylolisthesis