Microstructural evolution during in situ annealing of heavily cold-rolled aluminum has been studied by transmission electron microscopy, confirming that an important recovery mechanism is migration of triple junctions formed by three lamellar boundaries (Y-junctions). The migrating Y-junctions are pinned by deformation-induced interconnecting and lamellar boundaries, which slow down the recovery process and lead to a stop-go migration pattern. This pinning mechanism stabilizes the deformation microstructure, i.e. the structure is stabilized by balancing the driving and pinning forces controlling the rate of triple junction motion. As a consequence, recovery and the subsequent recrystallization are strongly retarded. The mechanisms underlying Y-junction motion and its pinning are analyzed and discussed.
Acta Materialia, 2015, Vol 86, p. 269-278
Aluminum; Annealing; Deformation structure; Transmission electron microscopy (TEM); Triple junction; Cold rolling; Deformation; Electron microscopy; Metal cladding; Transmission electron microscopy; Cold-rolled aluminum; Deformation microstructure; In-situ observations; Lamellar boundaries; Migration patterns; Recovery mechanisms; Recovery