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Jogs
and kinks are atomic scale changes in direction of a dislocation line.
Jogs are out of the slip plane and kinks lie in the dislocations slip plane.
For the edge dislocation shown, the jogs are of opposite sign (direction)
and the region between the jogs has moved up from the original slip plane
by one atomic spacing. This may be caused by the adsorption of vacancies
on the extra half plane.
A
slip plane has low energy locations for the dislocation line separated
by barriers of higher energy. At 0 K the dislocation will tend to lie in
just one minimum energy location. At finite temperature, the dislocation
line can move via thermal fluctuations and may occupy several distinct
minima along its length. The line section crossing the barriers between
these minima is the kink. For both jogs and kinks the Burgers vector
and line vector are those of the dislocation, the line vector being along
the direction of the jog or the kink. These features may therefore be of
a different type (edge, screw) than the dislocation and may restrict dislocation
glide.
From: Hull, "Introduction to Dislocations," Pergamon (1965) |
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