Diversity of the disorder and different-scale order during variations of severe deformation of copper

Abstract

The systematic features of structural changes in the atomic order and disorder in copper samples after severe deformation of a copper bar by shear rolling were studied. Shear rolling was performed in rolls with longitudinal and transverse grooves and with combined grooves of both types. The performed treatment made it possible to increase the strength characteristics by 30% with a simultaneous increase in the plastic characteristics by 15% as compared to the conventional technology using smooth rolls. A variety of the atomic order formed under the deformations used was revealed in the form of four different-size structural groups: small crystals with long-range order (102–103 Å), strain clusters with mesoscopic order (100–400 Å), amorphous clusters with incipient order (15–30 Å), and regions with disordered atoms. It was shown that conditions favorable for the formation of a perfect combination of fine crystalline (37%) and cluster (13%) different-scale groups of atomic order (50%) in disorder (50%) are created in the sample subjected to rolling in the combined mode. It was found that, in the sample produced by conventional rolling technology, regions with disordered atoms dominate (∼80%), whereas fine crystalline (16%) and cluster (4%) structural groups create an insufficiently organized atomic order for achieving high parameters of mechanical strength and plasticity.