Dislocation cannot end abruptly in a crystal: Free surface

Dislocation cannot end abruptly in a crystal: Free surface

[@TheSourav77]

@ 8:27 The dislocation line is the boundary between slip and no-slip regions in a slip plane. So, the line FP and PQ correspond to two different slip planes having a common burger's vector at all points. So, can we infer the two slip planes to be a part of the same zone, with the burger's vector as the zone axis?

[@introductiontomaterialsscience]

Since the dislocation line has two straight segments FP and PQ, the slip surface of this dislocation also has two planes meeting in a line. The Burgers vector is indeed along the line.

[@gunasai9039]

Sir, is it necessary to remove an entire half plane for the formation of edge dislocation? (or) If we remove some fraction of half plane only, is it still considered as an edge dislocation? The reason why I am asking this is, instead of cutting the plane PB @ 05:00 , if we add a plane at PB (of length PB), there will be an FP dislocation + another dislocation (which will end at the surface present below). But, an entire half plane is not missing in this case.

[@rashmeetkaur5756]

Plz tell.. Does the surface energy increase or decrease with increase in planar density?

[@poonamridhal5103]

Sir if we created a line defect in a material by alining some point defect , it will be considered as dislocation or something else.

[@sunilugadi3653]

professor...here can I consider, crystal as a grain of a poly crystalline material ?

[@introductiontomaterialsscience]

In a polycrystalline materials inter grain grains may not have any free surface. They are bounded by grain boundaries. In that case the dislocation will end at grain boundaries. However, if it is a surface grain then it can end on the free surface.