Effect of Zr on as-cast microstructure and properties of Cu-Cr alloy

Abstract

Cu-15Cr and Cu-15Cr-0.24Zr alloys were prepared by means of vacuum medium frequency induction melting technology. The effects of Zr on the as-cast microstructure of Cu-15Cr alloy were studied by means of scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and transmission electron microscopy (TEM). Besides, the effect of Zr on the tensile strength and electrical conductivity of Cu-15Cr alloy was also studied after heavy drawing deformation. The experimental results show that the addition of Zr leads to the formation of thin CuZr compound phase. Moreover, the formation of eutectic Cr phase is inhibited, so that the content of eutectic Cr is much lower than that of Cu-15Cr alloy. The size of dendritic Cr is refined as well. Furthermore, the addition of Zr improves the tensile strength of the alloy, which has little effect on the electrical conductivity. It is observed that when the dependent variable η is 6.44, the tensile strength and electrical conductivity of the alloy can reach 1023 MPa and 72 %IACS respectively, which increases 117 MPa and reduces only by 2 %IACS.