Static Recrystallization of Heavily Drawn OFHC Copper Wire at Low Annealing Temperature

摘要

Oxygen free high conducting (OFHC) copper rod was drawn, at room temperature, to various strains and annealed at 170 deg C to produce wires with recovered and recrystallized microstructures. The local orientations of the microstructures were measured by means of electron backscattered diffraction (EBSD) technique, from which inverse pole figures were calculated. This paper presents the results of three wires drawn to true strains of 2.31, 3.10 and 3.56. The low-strained wire did not recrystallize upon annealing, suggesting a recovery process. The recovered microstructure was characterized essentially by elongated grains with a <111>+<100> duplex fiber texture. The annealed microstructure of the intermediate strain was characterized by pockets of recrystallized regions, suggestive of the early stages of recrystallization. Nucleation process in this wire resulted in a random microtexture, and was attributed to nucleation at shear bands. Annealing of the high strained wire produced extensive, but incomplete recrystallization. The recrystallized grains were of different sizes and inhomogeneously distributed. Detailed analyses of the microtexture of the nucleating and recrystallized grains show a similar trend. At the initial stages of recrystallization, the nucleating grains are randomly oriented. However, as the grains grow in size, they progressively acquire a preferred orientation, a fiber texture.