SEM-EBSD analysis on early stage of recrystallization in Al–0.7%Mg–0.4%Si–0.2%Cr alloy

Abstract

Intermittent observations have been carried out on an early stage of recrystallization in Al–Mg–Si–Cr alloy with using an SEM-EBSD system. The specimen of Al–0.7%Mg–0.4%Si–0.2%Cr alloy was solution heat treated at 813 K for 3.6 ks, and then mechanically polished and finished by electropolishing. Vickers indentations were applied on the surface for landmarks. The specimen was cold-rolled at R. T. with about 30% of a reduction rate. After an EBSD observation, the specimen was cut into about 5×5×2 mm in size. Annealing the specimen at 673 K with using a molten salt bath, ion-polishing of the surface of the specimen for 180 s, and observing with the SEM-EBSD system were repeated. Intermittent observations on the same area were carried out during annealing up to 60 s. All the grains were rotated by cold-rolling. Deformation was inhomogeneity even in the same grain. Recovery was observed as formation of subgrains after annealing for 3 s. Subgrains having a similar orientation to the mother grain showed subgrain growth with annealing out of heavily deformed region. Such a subgrain growth was followed by formation of small grain without subgrains and surrounded by large angle grain boundary. Stress induced boundary migration was also observed.