Influence of High-Speed ECAP on the Structure and Properties of Copper and Copper Alloy of Cu-Cr System

Abstract

The paper presents the results of a study of changes in the structure during equal-channel angular pressing (1 and 4 cycles) with a deformation rate of 320 mm/s. It was found that a significant structure refinement of copper M1 and Cu-1.1Cr alloy to an ultrafine-grained state occurs already after 1 ECAP cycle. A predominantly band structure with a transverse size of fragments of ~ 200-300 nm occurs. A specific feature of the structural state is alignment of low-and high-angle boundaries by dislocations and absence of unbonded dislocations in the body of fragments. After 1 cycle of ECAP, practically no dispersed particles are observed in the body of Cu-1.1Cr alloy grains, and the electrical conductivity does not change in this case. The maximum hardening of copper M1 is observed after 4 ECAP cycles-1320 MPa with an electrical conductivity of 89% IACS for Cu-1.1Cr alloy, the maximum hardening is achieved after 1 cycle of ECAP and aging at 450 °C for 1 h-1655 MPa with an electrical conductivity of 77% IACS.