Effect of Y on the microstructure and physical properties of Cu-Zr-Mg-Y alloys

This work presents the development of two novel Cu-Zr-Mg(Y) alloys. The alloys were prepared using vacuum melting and show good conductivity and mechanical properties after solution treatment+60 % cold rolling + aging at 450 °C for 60 min.

The measurement results reveal that the Cu-Zr-Mg alloy has a microhardness of 165 ± 5 HV, an electrical conductivity of 68.5 ± 0.2 % IACS and a tensile strength of 483 ± 15 MPa while the Cu-Zr-Mg-Y alloy has a microhardness of 172 ± 6 HV, an electrical conductivity of 67.9 ± 0.2 % IACS and a tensile strength of 503 ± 12 MPa.

The addition of Y promotes the recovery and recrystallization of the alloys and causes the refinement of the grain size. The appearance of copper texture is the reason why the Cu-Zr-Mg-Y alloy has higher tensile strength in the rolling direction. The main phases of the Cu-Zr-Mg-Y alloy consist of Cu₅Zr and a small amount of Mg₂₄Y₅. The increment in precipitation strengthening is primarily attributed to the coherent Cu₅Zr phase within the matrix.