Properties of High Zirconium Cu-Zr-Cr Alloys and Their Isothermal Diagram of the Copper Corner

Some properties of Cu-Zr-Cr alloys containing more than about 0.5% zirconium and various amounts of chromium have been studied. The isothermal sections of copper corner of Cu-Zr-Cr equilibrium diagram mainly at 950° and 900°C have also been studied. The results obtained were as follows.(1) The properties of the alloys were little affected by the composition changes. The optimum composition of the alloys showing high strength and electric conductivity was in the range of about 0.5∼0.8%Zr and 0.5∼1.2%Cr.(2) The isothermal sections consisted of four different phase fields, i.e., α, α+Cr, α+Cr+Cu3Zr and α+Cu3Zr. The α phase field was extended toward the opposite direction to the copper corner. The same inter-phase relationship could also be found at lower temperatures. The properties of the alloys were considered to be well explained using the above diagram.