The Study of the Copper Alloy Structure and Properties

Abstract

This paper is devoted to the possibility of using tin as an alloying element in a copper alloy for the contact wire manufacture for high-speed electrified railways. To this end, laboratory experiments were carried out to determine the effect of tin on the structure, mechanical and electrical properties of samples, made of low-alloy system Cu-Sn alloys, under the cold deformation. Cast rods and rolled billets of CuSn0,2, CuSn0,4 and CuSn0,6 alloys are made. The cast rods macrostructure is studied. The analysis showed that with the introduction of tin into copper, there is no zone of columnar crystals in the macrostructure. Moreover, it was found that grains of α-solid solution of tin in copper have a shape close to equiaxial. A structure analysis of rolled billets showed that an increase in the deformation degree leads to grinding of crystalline grains. The mechanical properties of rolled billets were determined: ultimate tensile strength σU, offset yield strength σ0.2 and elongation δ50. The dependence of the electrical resistivity of rolled billets on the deformation degree and the tin content in the alloy is determined. Еhe higher the tin content in the alloy and the deformation degree is, the higher is the electrical resistivity. The electrical resistivity of samples, made of CuSn0.2 and CuSn0.4 alloys, coincides with the GOST R 55647-2018 requirements. The laboratory studies have shown that tin-containing copper alloys (Sn is up to 0.4 wt. %) can be recommended as a material for the manufacture of contact wire.