What are the major differences between edge and screw dislocations?

 The major differences between edge and screw dislocations are:

• Structure: An edge dislocation occurs when an extra half-plane of atoms is inserted into the crystal lattice, while a screw dislocation forms when the atomic planes spiral around the dislocation line like a helix.​

• Burgers Vector: In an edge dislocation, the Burgers vector is perpendicular to the dislocation line. In a screw dislocation, the Burgers vector is parallel to the dislocation line.​

• Stress Field: Edge dislocations create compressive stress above and tensile stress below the slip plane, whereas screw dislocations produce shear stress all around the dislocation line.​

• Movement: Edge dislocations move perpendicular to the dislocation line (glide/slip), while screw dislocations move parallel to the dislocation line and can undergo cross-slip.​

• Atomic Arrangement: Edge dislocations involve an extra half-plane of atoms, while screw dislocations involve a spiral ramp of atoms​

These differences affect how materials deform and respond to stress, making both types important in understanding plastic deformation in crystals