written 6.3 years ago by |
1) When the body is deformed under its load, the dislocation gets generated.
2) Basic observation made during the deformation was that as body is deformed the dislocation density increases, and second observation was the dislocation gets transmitted out of the body.
3) Both statements are contradictory but to justify both Frank and reed observed the source of generation of dislocation.
4) They observed that the dislocation occurred are transmitted along the slip plane in all the directions.
5) As the dislocations are pinned at both ends the shear stress acts over it during deformation slip plane.
6) The dislocation starts bowing due to application of shear stress in a circular manner, but end if it are still pinned.
7) The shear stress overcomes restoring force and bows the dislocation and starts expanding in all directions.
8) As due to shear stress overcoming the restoring force the bow begins to expand more and grows spontaneously.
9) As the bowing has expanded the opposite segments meet again an annihilate, the loop is formed and segment gets separated from loop.
10) The loop expands and gets transmitted outside, while segment performs the same procedure again and again.
11) This is how the segment dislocation transmits outside as well as dislocation density also increases which was observed by frank and reed.