Grain boundary distribution and texture in ultrafine-grained copper produced by severe plastic deformation

Microstructure, micro-and macrotexture and grain boundary distributions, which had been generated by severe plastic deformation (using the equi-channel angular technique) were studied. Grain refinement from 23 to 0.21 m accompanied by drastic changes of texture and GB distribution occurred during deformation. More than 90% of grain boundaries were found to be high-angle boundaries. The fractions of low-angle and twin boundaries were considerably lower than in the original state of the material. Generally, the GB distribution tended towards a random misorientation distribution. The formation of this type of microstructure can be explained by the concurrent action of dynamic recovery and a rotational mode of severe plastic deformation.