Properties and precipitates of the high strength and electrical conductivity Cu-Ni-Co-Si-Cr alloy

In this paper, a novel Cu-1.5Ni-1.1Co-0.6Si-0.1Cr (wt.%) alloy with high strength and electrical conductivity was designed. After aging, excellent properties of 857 +/- 12 MPa yield strength, 300 +/- 8 HV microhardness, 42.8 +/- 2.5% IACS conductivity, and 7 +/- 0.5% elongation were obtained. According to the atomic structure, part of Ni atoms in Ni2Si can be replaced by Co atoms to form nano-precipitates (Ni, Co)(2)Si. The alloy's high strength and conductivity are mainly attributed to the fine and uniformly distributed (Ni, Co)(2)Si and Cr nano precipitates. The alloy strength was also enhanced by twins, dislocations, and grain refining strengthening. Based on the investigations of deformation microstructure and the orientation relationship between the (Ni, Co)(2)Si precipitates and the Cu matrix, the main reason for elongation increase is attributed to the formation of deformation twins and the small lattice mismatch strain at the coherent interfaces of precipitates and the Cu matrix. (C) 2021 Published by Elsevier Ltd on behalf of Chinese Society for Metals.

Automated summary

A novel Cu alloy with high strength and electrical conductivity was designed in this study, and excellent properties were obtained after aging. The high strength and conductivity of the alloy are mainly attributed to the nano-precipitates and the fine and uniformly distributed nano precipitates. The increase in elongation is mainly attributed to the formation of deformation twins and the small lattice mismatch strain at the coherent interfaces of precipitates and the Cu matrix.