Changes

Table 5.18: Mechanical Properties of Selected Copper-Beryllium Alloys (2 Teile!)

As the phase diagram shows, copper-chromium has a similar hardening profile compared to CuBe ''(Fig. 5.32)''. In the hardened stage CuCr has limitations to work hardening. Compared to copper it has a better temperature stability with good electrical conductivity. Hardness and electrical conductivity as a function of cold working and precipitation hardening conditions are illustrated in Figs. 5.33-5.35 ''(Tables 5.19 and 5.20)''.

The solubility of Zirconium in copper is 0.15 wt% Zr at the eutectic temperature of 980°C ''(Fig. 5.36)''. Copper-zirconium materials have a similar properties spectrum compared to the one for copper-chromium materials. At room temperature the mechanical properties of copper-zirconium are less suitable than those of copper chromium, its temperature stability is however at least the same.

The earlier used CuCr and CuZr materials have been partially replaced over the years by the capitation hardening three materials alloy CuCr1Zr. This material exhibits high mechanical strength at elevated temperatures and good oxidation resistance as well as high softening temperatures. In its hardened condition CuCr1Zr has also a high electrical conductivity (Bild 5.37). Their usage extends from mechanically and thermally highly stressed parts such as contact tulips in high voltage switchgear to electrodes for resistance welding.