Study on the modification mechanism of La Y Zr on high strength and high conductivity of C7035 copper alloy

Abstract

In order to study the effect of multi-element doping on the mechanical and electrical conductivity of copper alloys, first-principles calculations and experiments based on density functional theory were used to explore the coupling mechanism of multi-element doping on the improvement of mechanical and electrical conductivity of copper alloys at microscopic and macroscopic scales. The results show that the factors influencing the strength and electrical conductivity in copper alloys are as follows: 1) The complex phases (LaCu₆, YCu₅, ZrCu₅) formed by doped elements and Cu, 2) the complex phases formed by the synergy of doped elements, and 3) the twin and dislocation structures induced by doping. The precipitated phase formed by La element has a lamellar structure, which improves the toughness of the alloy on the basis of losing part of the strength. Due to the high electrical conductivity of the precipitated phase LaCu6, the electrical conductivity of the alloy has increased by up to 23.8 %. The precipitated phase formed by Zr has a moderate size. It not only enhances the strength of the alloy but also improves the electrical conductivity, with the electrical conductivity increasing by up to 19.2 %. Y has a significant effect on enhancing the strength, but it has a negative impact on the electrical conductivity, with the electrical conductivity decreasing by at least 24.5 %.