Regulation of primary phase in Cu-Cr-Zr alloy and its effect on nano-structure and properties

In this study, Cu-0.8Cr-0.1Zr alloy was prepared by vacuum horizontal continuous casting method. The effect of different thermo-mechanical treatment processes on the properties was studied, and the micro-structure evolution at different stages of thermo-mechanical treatment were observed by SEM, EBSD and (HR)TEM. The results showed that the optimal comprehensive performance of tensile strength (803 MPa) and conductivity (76% IACS) was obtained by three-stage drawing and thermal treatment (primary 43.75% drawing and solution treatment at 950 degrees C for 60 min + secondary 97.2% drawing and aging at 500 degrees C for 30 min + tertiary 75% drawing). Through the microstructure characterization, it was found that the mor-phology and distribution of the Cr-rich primary phase can be regulated by solution treatment, and inherited during the thermo-mechanical treatment. It acts as a nucleation point and hard point, thereby refining the grain and improving the strength of the alloy. Additionally, it reduces the number of solid solution atoms in the matrix and prevents the loss of conductivity. Furthermore, drawing with a large amount of deformation can produce a nano-lamellar structure with high temperature stability, and drawing after high temperature aging can induce substructure formation. The combination of nano-lamellar structure and substructure further improves the strength.(c) 2022 Elsevier B.V. All rights reserved.

Automated summary

Different thermo-mechanical treatment processes were studied on Cu-0.8Cr-0.1Zr alloy, and the optimal comprehensive performance was achieved through a three-stage drawing and thermal treatment. The morphology and distribution of the main phase can be regulated by solution treatment, thereby improving the strength of the alloy.