Deformation microstructure and properties control of Cu-0.6Cr alloy in cryo-equal channel angular pressing

Cu-0.6Cr alloy was extruded by liquid nitrogen cooling equal channel angular pressing (ECAP) route-Bc and aging treated at 400 & DEG;C-500 & DEG;C; the structure and orientation distribution of the alloy were detected by optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), electron back-scattered diffraction (EBSD) and TEM. The purpose is to detect the influence of deformation conditions and aging treatment on the microstructure and properties of the materials, and to analyzed the microscopic mechanism of the precipitates formation process and transformation. The results show that the cryo-ECAP-Bc deformation will accelerate the interaction between the microstructure and texture of the Cu-0.6Cr alloy, and reduce the limitation size of the grains after deformation. Strain increase can promote increasing the amounts of micro/nano precipitates discontinuous distribution on the grain boundaries. After 4 passes of extrusion and aging at 450 & DEG;C, the tensile strength, hardness and elongation of the material reach to 555.0 MPa, HV 167.3 and 13.1%, respectively, and the conductivity exceeds 84%IACS. The synergistic effect of microalloying, solid solution, cryo-ECAP and aging, and the formation of {111} and {111} textures are beneficial to improving the conductivity of the alloy simultaneously.

Automated summary

The Cu-0.6Cr alloy was processed by cryo-ECAP-Bc and aging treatment, and the effects of deformation conditions and aging on the microstructure and properties of the alloy were investigated. The cryo-ECAP-Bc deformation accelerated the interaction between microstructure and texture, reducing grain size limitation. Strain increase promoted the formation of micro/nano precipitates on grain boundaries. After 4 passes of extrusion and aging at 450°C, the material exhibited high strength, hardness, elongation, and conductivity, attributed to the synergistic effect of microalloying, solid solution, cryo-ECAP, and aging.