The evolution of microstructure and texture

and their effects on the microhardness of high purity oxygen free copper tube during deformation were investigated by electron backscattered diffraction technology and hardness testing.The results reveal that for low strains

the microstructure is elongated along the axial direction

and the average grain size is decreased while the low angle grain boundaries are increased as strain increase

and thus the microhardness value is increased significantly.After deformation

there exists a major<111>fiber texture with a secondary<001> one paralleling to the axial direction.For high strains above 77%

both the grain size and low angle grain boundary are decreased slightly

and the microhardness is increased to some extent as the strain increase.The co-action of working hardening and the deformation result in the increase of<001>texture and<111>

which is great different from the conventional cases.The initial deformation is suggested to favor detwinining

while further deformation induces reappearing of twins.