Microstructure and properties of high strength, high conductivity Cu-2.5Fe-0.3Cr-0.3Mg-0.2Si-0.1Ca-0.1Zr alloy treated by multi-stage thermomechanical treatment

In the Cu-2.5Fe-0.3Cr-0.3 Mg-0.2Si-0.1Ca-0.1Zr alloy, a double-scale (micro and nano) FeCrSi second phase has been generated. The orientation relationship between nano-precipitates and the matrix is: (111)Cu//(202)FexCr(3-x)Si, 11¯0Cu//11¯1¯ FexCr(3-x)Si. The influence of the thermomechanical treatment process on the microstructure, mechanical properties and electrical conductivity of the alloy is explored. Results indicate that the final alloy has excellent properties. The hardness, yield strength, tensile strength and electrical conductivity of the final alloy are 204 HV, 635 MPa, 649 MPa and 63.57 %IACS, respectively. The calculations show that precipitation strengthening and dislocation strengthening have essential contributions to the strength of the final alloy. The former mainly comes from the strengthening effect of the FeCrSi nano-precipitates, and the latter is related to the multi-stage thermomechanical treatment process. •A novel high-strength and high-conductivity Cu-2.5Fe-0.2Si-0.3 Mg-0.1Ca-0.3Cr-0.1Zr alloy is designed.•A double-scale (micro and nano) FeCrSi second phase has been generated in the designed alloy.•FeCrSi nano-precipitates have a remarkably significant contribution to the strength of the alloy.•The tensile strength and electrical conductivity are 649 MPa and 63.57 %IACS, respectively.