Recovery in aluminium studied by an in situ technique in a high voltage electron microscope

Abstract

Recovery in aluminium has been studied by in situ technique with the aid of a high voltage electron microscope. It is shown how the dislocation density continuously decreased as the recovery proceeded. The recovery process changed the distribution of dislocation link lengths in such a way that the number of shorter links sharply decreased while there was a slight increase of the number of longer links. The observed recovery of the dislocation structure can satisfactorily be described by the dislocation network growth theory. In the formation of subgrain boundaries, high-angle grain boundaries and twin boundaries played an important role. They were often found to act as “nucleation sites” for the subboundaries. At high temperatures subgrains rapidly grew and coalesced. The growth can satisfactorily be described by analogy with the growth of dislocation network.