Texture and Grain Boundary Character Distribution in a Thermomechanically Processed OFHC Copper

The effect of texture on grain boundary character distribution (GBCD) in thermomechanically processed oxygen-free high-conductivity copper has been investigated. Copper samples were cold rolled to a reduction in thickness of 50% and then annealed for 60 min in the range of 400–600°C. GBCD and texture were measured using electron backscatter diffraction. The fraction of special boundaries (Σ3, Σ9, and Σ27) varied from 59% to 71%, with the maximum in the sample annealed at 500°C. The results indicate that cold rolling provided a strong texture of brass type. It was found that the sample annealed at 500°C have texture components of cube, Goss, rotated-Goss, and Y orientations. These texture components were in relation with the formation of annealing twins and Σ3 boundaries. It was also shown that twin-induced GBCD evolution occurred by strain-induced boundary migration, multiple twinning, and conventional recrystallization. Annealing at 600°C caused full recrystallization and grain growth, showing a strong cube recrystallization texture. The grain growth was found to hinder the formation of special boundaries.