Because of their good elastic spring properties and formability, the copper-tin alloys CuSn6 and CuSn8 are standard materials for spring contact elements in electromechanical components, such as connectors, switches and relays (<xr id="tab:Physical Properties of Copper-Tin Alloys"/><!--(Tab. 5.9)--> and <xr id="tab:Mechanical Properties of Copper-Tin Alloys"/><!--(Tab.5.10)-->). Besides these, other alloys such as CuSn4, CuSn5 and the multi-metal tin bronze CuSn3Zn9 have significant usage – mainly in North America. <!--5.10--><xr id="fig:Phase diagram of the Cu-Sn system for the range of 0 – 30 wt% Sn"/> shows the copper rich side of the phase diagram for the CuSn system. The mechanical property values achieved by cold forming are superior to these of the brass alloys (<xr id="fig:Mechanical properties of tin bronze depending on the tin content (cold working 0 and 50%)"/><!--(Fig. 5.11)-->). They increase significantly with increasing Sn content. The work hardening and softening behavior are shown for the example of CuSn8 in <xr id="fig:Strain hardening of CuSn8 by cold working"/><!--Figures 5.12--> and <xr id="fig:Softening of CuSn8 after 3 hrs annealing after 50% cold working"/><!--Fig. 5.13-->. The stress relaxation properties for CuSn alloys are good for up to 100°C, deteriorate however quickly for temperatures above 150°C.

Despite its lower electrical conductivity, the good spring properties, high corrosion resistance and the good workability make copper-nickel-zinc alloys a frequently used spring contact carrier in switches and relays. As illustrated in the phase diagram, the most commonly used materials are in the &alpha; -range which means that they are single-phase alloys (<xr id="fig:Copper rich region of the ternary copper-nickel-zinc phase diagram with indication of the more commonly available german silver materials"/><!--(Fig. 5.14)-->). The formability and strength properties of german silver are comparable to those of the copper-tin alloys. The work hardening and softening behavior is illustrated on the example of CuNi12Zn24 in <xr id="fig:Strain hardening of CuNi12Zn24 by cold working"/><!--Figures 5.15--> and <xr id="fig:Softening of CuNi12Zn24 after 3 hrs annealing after 50% cold working"/><!--5.16-->.

[[File:Copper rich region of the termary copper nickel zinc phase diagram.jpg|right|thumb|Figure 10: Copper rich region of the ternary copper-nickel-zinc phase diagram with indication of the more commonly available german silver materials]]

Besides the low-allowed CuAg0.1, other copper materials with higher silver contents (2-6 wt%) are also used as contacts carrier materials. Some of them contain additional 1.5 wt% Cd. The phase diagram <xr id="fig:Phase diagram of copper-silver for the range of 0 – 40 wt% silver"/><!--(Fig. 5.17)--> shows, that in principle the CuAg alloys can be precipitation hardened, but the possible increase in mechanical strength is rather small.

Copper-silver alloys have good spring properties and compared to other spring materials have a high electrical conductivity (<xr id="tab:tab5.13"/> <!--(Tab. 5.13)--> and <xr id="tab:tab5.14"/><!--(Tab. 5.14)-->). The mechanical strength values in the strongly worked condition are comparable to those of the copper-tin alloys. Work hardening and softening behavior are shown for the example of CuAg2 [[#figures5|(Figs. 13 – 15)]]<!--(Figs. 5.18 – 5.20)-->. For the relaxation behavior, the silver bronzes are superior to German silver and tin bronze.