Dislocation theory

Transmission electron microscope (TEM)
TEM is the most powerful technique used to study dislocations.
• A thin foil of 100 nm is prepared using
electropolishing from a ~1 mm thick sheet.
• This thin foil is transparent to electrons in
the electron microscope and this makes it
possible to observed dislocation
networks, stacking faults, dislocation
pile-ups at grain boundaries.
• By using the kinematic and dynamic
theories of electron diffraction it is possible
to determine the dislocation number,
Burgers vectors and slip planes.
32500 x
Dislocation network in cold-worked
aluminium.
Note: The sampling area is small therefore the properties
observed cannot represent the whole materials.
Suranaree University of Technology May-Aug 2007
Tapany Udomphol