Shows a recrystallised grain which is relatively free of dislocations, surrounded by a deformed matrix which has a high dislocation density. The recrystallised grain contains annealing twins (parallel bands with different contrast).

Recrystallised grains which which show uniform contrast because they are relatively free of dislocations, surrounded by a deformed matrix which has a high dislocatin density. The recrystallised grain contains annealing twins (parallel bands with different contrast. The steps at the top left-hand corner are simply steps in annealing twin boundaries.

A mixture of deformed and recrystallised grains.

A beautiful picture of annealing twins. Notice how the ends of annealing twins are flat, the shape being determined by a minimisation of interfacial energy. Mechanical twins, by contrast, are lenticular (lens like) with sharply pointed ends to minimise the strain energy due to the twinning shear. Annealing twins do not cause any deformation so strain energy minimisation is not an issue. This is also the reason why there is no strain field contrast visible at the tips of the annealing twins.

Shows a mixture of recrystallised and deformed grains. There are some stacking faults (ribbon like contrast) in the recrystallised grains; austenitic stainless steels have a relatively low stacking fault energy.

Shows the nucleation of recrystallization at grain boundaries. Scanning electron micrograph of a perfectly flat sample of austenitic stainless steel which has been partially recrystallised. The grains are imaged using electron channelling contrast. The 18/10 steel has been annealed at 1023 K for 20 minutes. New grains can be seen to nucleate at the prior grain boundaries of the deformed structure.