The Formation of Twins in Recrystallized Binary Al-1.3%Mn

Local texture analysis in sheets of cold-rolled and recrystallization-annealed binary Al-1.3%Mn revealed a number of twin grain boundaries, including one twin chain of third generation. The formation mechanism of these twins was traced by means of electron backscattering diffraction analysis of the twinned grains and the surrounding matrix at the early stages of recrystallization. The results obtained suggest that the twins do not form by conventional recrystallization twinning, but the twin boundaries are rather the result of an impingement between newly formed recrystallized grains and subgrains of the as-deformed matrix, which were already in twin relation. Consequently, the formation of twins does not lead to the generation of new orientations and, hence, does not affect the recrystallization texture. Besides the twins, other coincidence site–lattice orientation relations were frequently observed, which also could be tracked to the as-deformed state.