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 Σ9, while that between Brass and Cube grains to be Σ5. Frequency of Σ9 and Σ5 boundaries increased quickly at early stage and then reduced gradually with the process of recrystallization. Annealing at a higher temperature (320 °C) was found to be beneficial for the formation of Σ9 boundary, while at lower one (300 °C), Σ5 boundary became dominant. Besides, with temperature decreasing from 320 to 300 °C, the mobility of Σ9 boundaries was greatly degraded, but relatively, Σ5 boundaries still behaved highly mobile. Principally, the preferred growth of recrystallized Goss and Cube grains was respectively attributed to the high mobility of Σ9 and Σ5 boundaries with high index planes that the square sum of plane index was larger than 3.