Effect of annealing on microstructure and tensile properties of cold-rolled Cu-2.7Be sheets

The cold rolled Cu-2.7Be sheets were annealed at different temperatures. The evolution of microstructure, texture and tensile properties was investigated using electron backscatter diffraction (EBSD), transmission electron microscopy (TEM) and tensile tests, respectively. Results showed that preponderant ∑ 3 annealing twins were produced during recrystallization. The ∑ 3 fraction and average grain size increased with increasing annealing temperature. Besides, it turned out that the extension and depletion of twin boundaries occurred simultaneously during grain growth process, affecting the ∑ 3 fraction. Recrystallization texture became relative isotropic because of twinning mechanism which involved the formation of new orientations from the parent grain. It was noteworthy that the weak recrystallization cube texture was observed, which was attributed to appearance of preponderant twin boundaries. Tensile tests results showed that twin boundaries should be considered as effective obstacles to dislocations motion, similar to regular grain boundaries.