Creation and processing of copper alloys doped with chromium, zirconium and vanadium

Abstract

The rapid development of mechanical engineering and electrical engineering requires alloys that have high electrical conductivity and a high level of mechanical properties, including strength at elevated temperatures. Pure and low-alloyed copper are ductile, but low-strength materials, which prevents their application in many areas. The solution of such problem can be in alloying with metals that would increase strength characteristics while maintaining electrical conductivity as much as possible, including at high current and temperature loads. The main alloying elements analyzed in this work as effective strengthening components were Cr, Zr, and V. It is shown that the increase in strength while maintaining electrical conductivity depends to a greater extent on the chromium content, the concentration of which in alloys can reach 5-10 wt. %. It was established that to achieve optimal characteristics of strength and electrical conductivity, the concentration of chromium can be close to 0,1 wt. %, and zirconium - up to 0,2 wt. %. At the same time, both for alloys with a high chromium content and in low-alloyed compositions, the characteristics of strength and electrical conductivity can differ by only 10-20%. In the vast majority of cases, copper alloys with chromium and zirconium undergo a specific, sometimes compositional and multi-stage, deformation treatment, after which a fine crystalline structure with nano-sized allocations of strengthening dispersoid phases can be formed. All considered alloys show similar technological features of obtaining a high level of final properties - homogenization and tempering from temperatures of 900-1000 °С and aging at 500 °С for 2 hours or more. At the same time, the higher the content of chromium and zirconium, the more difficult the deformation and heat treatments will be. Additional microalloying with vanadium in the amount of up to 0.2 wt. % may increase strength without a noticeable decrease in electrical conductivity and without the need for the complication of deformation and heat treatments. Keywords: alloying of copper alloys, Cu-Cr-Zr, Cu-Cr-Zr-V, heat treatment, deformation, electrical conductivity.