Coincidence site lattice boundary mechanism for the preferred growth of Goss and Cube grains during annealing in an Al-Cu-Mg alloy

The formation mechanism of recrystallized textures in an Al-Cu-Mg alloy was investigated by means of three dimensional orientation distribution functions (ODFs) and in-situ electron back-scattered diffraction (EBSD). The results showed that in the hot-rolled alloy with a very sharp Brass texture but weak Copper and S orientations, both Goss and Cube grains were recrystallized out of parent Brass matrix. In-situ EBSD analysis revealed that characteristic boundary between Brass and Goss grains to be Sigma 9, while that between Brass and Cube grains to be Sigma 5. Frequency of Sigma 9 and Sigma 5 boundaries increased quickly at early stage and then reduced gradually with the process of recrystallization. Annealing at a higher temperature (320 degrees C) was found to be beneficial for the formation of Sigma 9 boundary, while at lower one (300 'C), Sigma 5 boundary became dominant. Besides, with temperature decreasing from 320 to 300 degrees C, the mobility of Sigma 9 boundaries was greatly degraded, but relatively, Sigma 5 boundaries still behaved highly mobile. Principally, the preferred growth of recrystallized Goss and Cube grains was respectively attributed to the high mobility of Sigma 9 and Sigma 5 boundaries with high index planes that the square sum of plane index was larger than 3.