CALPHAD-assisted composition and processing design of high-strength and high-conductivity copper alloy

Abstract

In this work, a Cu–Cr–Ag–Mg–Sn alloy was developed assisted by a CALPHAD technique, by which a suitable chemical composition (Cu-0.5Cr-0.1Ag-0.05Mg-0.05Sn) and processing parameters were efficiently designed. The achieved alloy exhibited yield strength and conductivity values of 642 MPa and 74.2% IACS, respectively, which greatly surpassed the commercial C18150 alloy. Transmission electron microscopy observation demonstrated that such a good comprehensive performance was attributed to numerous nano-scale Cr precipitates that possessed a strong coherent relationship with the Cu matrix. Further microstructure characterizations demonstrated that these beneficial Cr precipitates were associated with subgrain boundaries in the alloy introduced by a cold-rolling→short-time secondary solid solution. Atom probe tomography analysis demonstrated that Sn atoms that readily attached to the surfaces of Cr precipitates.