Recrystallization behaviour of plane strain deformed Al-Mn-Mg-Sc-Zr alloy

摘要

Early stages of recrystallization were observed for the Al-Mn-Mg-Zr(Sc) aluminium alloy containing a fine second phase particles. The samples were plane strain compressed to 40%, 60% and 83% and then annealed. The processes of the recovery and the nucleation of new grains were analysed with the use of scanning electron microscopy equipped with a high resolution electron backscattered diffraction facility. The deformed alloy contained a structure of flat grains situated parallel to the compression plane. After annealing, the structure coarsened. However, the growth of the new grains was strongly hindered by the presence of particles, and the elongated shape of the deformed grains was conserved up to the later stages of recrystallization. In the case of the samples deformed up to 40%, the structure was transformed by the mechanism of continuous recrystallization, whereas, in the case of the samples deformed up to 60% or 83%, both mechanisms - of continuous and discontinuous recrystallization - were valid. A particular role in the rise of the nuclei and the structure spheroidization is attributed to the thermally activated migration of the low-angle grain boundaries and the movement of the dislocations stored inside the cells. This leads to an increase of the misorientation angles across the pre-existing low-angle boundaries.