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Table 5.18: Mechanical Properties of Selected Copper-Beryllium Alloys (2 Teile!)
=====5.1.6.2 Other Precipitation Hardening Copper Alloys=====
======5.1.6.2.1 Copper-Chromium Alloys======
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)''.
Copper-chromium materials are especially suitable for use as electrodes for resistance welding. During brazing the loss in hardness is limited if low melting brazing alloys and reasonably short heating times are used.
Fig. 5.32:
Copper corner of the copper-chromium
phase diagram for up to 0.8 wt% chromium
Fig. 5.33:
Softening of precipitation-hardened
and subsequently cold
worked CuCr1 after
4hrs annealing
Fig. 5.34 a:
Electrical conductivity of
precipitation hardened
CuCr 0.6 as a function of
annealing conditions
Fig. 5.34 b:
Hardness of
precipitation hardened
CuCr 0.6 as a function
of annealing conditions
Fig. 5.35:
Electrical conductivity
and hardness of precipitation
hardened CuCr 0.6 after
cold working
Table 5.19: Physical Properties of Other Precipitation Hardening Copper Alloys (2 Teile!)
Table 5.20: Mechanical Properties of Other Precipitation Hardening Copper Alloys
======5.1.6.2.2 Copper-Zirconium Alloys======
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.
