screw and edge dislocations
Post on 03-Feb-2016
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Chapter 4-
Line Defects
• are line defects,• slip between crystal planes result when dislocations move,• produce permanent (plastic) deformation.
Dislocations:
• before deformation • after deformation
slip steps
Chapter 4-
Screw Dislocation
Atomic distortion associated with a screw dislocation is shear.
There is no extra half plane. A spiral path could be traced around the dislocation line
Burger vector for Screw - b is parallel to lineDislocations play an important role in the plastic deformation of crystalline materials.
Chapter 4-
Edge & Screw Dislocation
Chapter 4-
Edge & Screw DislocationFor metals, the Burgers vector of a dislocation will be in the close packed direction and its magnitude will be equal to one inter-atomic spacingA dislocation may change its character from edge to screw to mixed within a crystal but its Burgers vector is an invariant.
Chapter 4-
Edge & Screw Dislocation
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