Study on the high-strength and high-conductivity modification mechanisms of C7035 copper alloy induced by La and Sc doping

The effects of multi-element doping on mechanical and electrical properties of C7035 copper alloy were investigated by first principles calculation and experiment based on density functional theory (DFT). The results show that the addition of lanthanum (La) significantly improves the electrical conductivity of copper alloy, mainly because the precipitated phase of lanthanum (La) has high electrical conductivity, and promotes the formation of high-density twins in 0 Cu matrix. The electrical conductivity of the C7035 alloy doped with La reaches 80.19 % of IACS, which is 44.17 % higher than that of the alloy without La. In addition, the incorporation of scandium (Sc) increased the yield strength of the alloy to 635.63 MPa, an improvement of 25.65 %, due to the excellent mechanical properties of the ScCu4 precipitated phase. The highly conductive NiSi precipitated phase is formed by the copper alloy doped with La and Sc simultaneously. Compared with the undoped alloy, the yield strength and conductivity of the co-doped alloy are 672.27 MPa, 62.7 %, 32.89 % and 12.73 % respectively. In summary, the coupling doping of La and Sc improves the mechanical and electrical properties of C7035 copper alloy, which provides theoretical guidance for the design of high-strength and high-conductivity copper alloys.