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Alloys like brasses (CuZn), tin bronzes (CuSN), and German silver (CuNiZn), for which the required hardness is achieved by cold working are defined as naturally hard alloys. Included in this group are also the silver bronzes (CuAg) with 2 – 6 wt% of Ag.
====<!--5.1.4.1 -->Copper-Zinc Alloys Test (Brasses)====
Copper-zinc alloys are widely used as contact carrier materials in switching devices for electrical power engineering because of their high electrical conductivity, the higher mechanical strength combined with good formability compared to pure copper <xr id="tab:tab5.7Physical_Properties_of_ Selected_Copper_Zinc_Alloys"/> <!--(Tab. 5.7) --> and <xr id="tab:tab5.8Mechanical_Properties_of_Selected_Copper_Zinc_Alloys"/> <!--(Tab. 5.8)-->, and at the same time their reasonable economic costs. Especially suitable are the brasses with up to 37 wt% Zn content which are according to the phase diagram all made up from the " α -phase of the CuZn system <xr id="fig:Phase diagram of copper-zinc for the range of 0-60 wt% zincPhase_diagram_of_copper_zinc_for_the_range_of_0_60_wt_zinc"/><!--(Fig. 5.5)-->. It is important to note the strong dependence of the electrical conductivity and mechanical strength on the zinc content <xr id="fig:Mechanical properties of brass depending on the copper content (after cold working of 0 and 50%)Mechanical_properties_of_brass_ depending_on_the_copper_content_after_cold_working_of_0_and_50"/><!--(Fig. 5.6)-->.
<figtable id="tab:tab5.7Physical_Properties_of_ Selected_Copper_Zinc_Alloys"><caption>'''<!--Table 5.7: -->Physical Properties of Selected Copper-Zinc Alloys''' </caption>
{| class="twocolortable" style="text-align: left; font-size: 12px"
!Composition<br />[wt%]
!Density<br />[g/cm<sup>3</sup>]
!colspan="2" style="text-align:center"|Electrical<br />Conductivity<br />[MS/m] [% IACS]
!Electrical<br />Resistivity<br />[μΩ·cm]
!Thermal<br />Conductivity<br />[W/(m·K)]
!Softening Temperature<br />(approx. 10% loss in<br />strength)<br />[°C]
!Melting<br />Temp Range<br />[°C]
|-
!
!
!
![MS/m]
![% IACS]
!
!
!
!
!
!
|-
|CuZn5<br />CW500L<br />C21000
<figtable id="tab:tab5.8Mechanical_Properties_of_Selected_Copper_Zinc_Alloys"><caption>'''<!--Table 5.8: -->Mechanical Properties of Selected Copper-Zinc Alloys'''</caption>
{| class="twocolortable" style="text-align: left; font-size: 12px"
than the standard brass alloys. Even so this material is a naturally hardening alloy, a suitable heat treatment allows to further increase its strength.
<xr id="fig:Phase diagram of copper-zinc for the range of 0-60 wt% zincPhase_diagram_of_copper_zinc_for_the_range_of_0_60_wt_zinc"/> <!--Fig. 5.5: --> Strain hardening of Ag 99.95 by cold working
<xr id="fig:Mechanical properties of brass depending on the copper content (after cold working of 0 and 50%)Mechanical_properties_of_brass_ depending_on_the_copper_content_after_cold_working_of_0_and_50"/> <!--Fig. 5.6: --> Mechanical properties of brass depending on the copper content (after cold working of 0 and 50%)
<xr id="fig:Strain hardening of CuZn36 by cold forming"/> <!--Fig. 5.7: --> Strain hardening of CuZn36 by cold forming
<xr id="fig:Softening of CuZn36 after 3 hrs annealing after 25% cold working"/> <!--Fig. 5.8: --> Softening of CuZn36 after 3 hrs annealing after 25% cold working
<div class="multiple-images">
<figure id="fig:Phase diagram of copper-zinc for the range of 0-60 wt% zincPhase_diagram_of_copper_zinc_for_the_range_of_0_60_wt_zinc">
[[File:Phase diagram of copper zinc.jpg|left|thumb|<caption>Phase diagram of copper-zinc for the range of 0-60 wt% zinc</caption>]]
</figure>
<figure id="fig:Mechanical properties of brass depending on the copper content (after cold working of 0 and 50%)Mechanical_properties_of_brass_ depending_on_the_copper_content_after_cold_working_of_0_and_50">
[[File:Mechanical properties of brass depending on the copper content.jpg|left|thumb|<caption>Mechanical properties of brass depending on the copper content (after cold working of 0 and 50%)</caption>]]
</figure>
<div class="clear"></div>
====<!--5.1.4.2 -->Copper-Tin Alloys (Tin Bronze)====
Because of their good elastic spring properties and formability the copper-tin alloys CuSn6 and CuSn8 are standard materials for spring contact elements in electrome-chanical components such as connectors, switches, and relays <xr id="tab:tab5.9Physical Properties of Copper-Tin Alloys"/> <!--(Tab. 5.9) --> and <xr id="tab:tab5.10Mechanical Properties of Copper-Tin Alloys"/><!--(Tab.5.10)-->. Besides these other alloys such as CuSn4 and CuSn5 and the multi-metal tin bronze CuSn3Zn9 have significant usage – mainly in North America.Figure <!--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 softeningbehavior 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.
<figtable id="tab:tab5.9Physical Properties of Copper-Tin Alloys"><caption>'''<!--Table 5.9: -->Physical Properties of Copper-Tin Alloys''' </caption>
{| class="twocolortable" style="text-align: left; font-size: 12px"
!Composition<br />[wt%]
!Density<br />[g/cm<sup>3</sup>]
!colspan="2" style="text-align:center"|Electrical<br />Conductivity<br />[MS/m] [% IACS]
!Electrical<br />Resistivity<br />[μΩ·cm]
!Thermal<br />Conductivity<br />[W/(m·K)]
!Softening Temperature<br />(approx. 10% loss in<br />strength)<br />[°C]
!Melting<br />Temp Range<br />[°C]
|-
!
!
!
![MS/m]
![% IACS]
!
!
!
!
!
!
|-
|CuSn4<br />CW450K<br />C51100
</figtable>
<figtable id="tab:tab5.10Mechanical Properties of Copper-Tin Alloys"><caption>'''<!--Table 5.10: -->Mechanical Properties of Copper-Tin Alloys''' </caption>
{| class="twocolortable" style="text-align: left; font-size: 12px"
!Hardness<br />Condition
!Tensile Strength R<sub>m</sub><br />[MPa]
!0,2% YieldStrengthYield Strength<br />R<sub>p02</sub><br />[MPa]
!Elongation<br />A<sub>50</sub><br />[%]
!Vickers<br />Hardness<br />HV
!Spring Fatigue<br />Limit σ<sub>BW</sub><br />[MPa]
|-
|CuAg0,10CuSn4|R 200290<br />R 360|200 - 250<br />360|120<br />320|> 40<br />> 3|40<br />90|0 x t390<br />0.5 x t|0 x t<br />0.5 x t|240|120|-|CuFe0,1P|R 300480<br />R 360540<br />R 420610|300 290 - 380390<br />360 390 - 440490<br />420 480 - 500|> 260570<br />> 300540 - 630<br />> 350≥ 610|> 10≤ 190<br />> 3≥ 210<br />> 2|80 - 110≥ 420<br />110 - 130≥ 490<br />120 - 150≥ 540|0 x t<br />0.5 x t40<br />1.5 x t|0 x t13<br />0.5 x t<br />1.5 x t|250|160|-|CuSn0,15|R 2504<br />R 300<br />R 360<br />R 4202|250 70 - 320100<br />300 115 - 370155<br />360 150 - 430180<br />420 170 - 490|> 200<br />> 250<br />> 300<br />> 350≥ 190|> 90 x t<br />> 40 x t<br />> 30 x t<br />> 2|60 - 90<br />85 - 110<br />105 - 130<br />120 - 1400 x t
|0 x t<br />0 x t<br />0 x t<br />1 x t
|0 x t<br />0 x t<br />0 x t<br />1 x t420|250|160200
|-
|CuFe2PCuSn5|R 370310<br />R 420400<br />R 470490<br />R 520550<br />R 630<br />R 690|370 310 - 390<br />400 - 430500<br />420 490 - 480580<br />470 550 - 530640<br />520 630 - 580720<br />≥ 690|≤ 250<br /> 300≥ 240<br />≥ 430<br /> 380≥ 510<br />> 430≥ 600<br />> 470≥ 670|45<br /> 617<br />> 410<br />> 46<br />> 3|115 75 - 135105<br />130 120 - 150160<br />140 160 - 160190<br />180 - 210<br />150 200 - 170230<br />≥ 220|0 x t<br />0.5 x t<br />0.5 x t<br />0 x t<br />1 x t|0 x t<br />0.5 x t<br />0.5 x t<br />1 x t<br />2 x t|340460|200220
|-
|CuNi2SiCuSn6|R 430350<supbr />2)R 420<br /sup>R 500<br />R 510560<supbr />2)R 640<br /sup>R 720|350 - 420<br />R 600420 - 520<supbr />2)500 - 590<br /sup>|430 560 - 520650<br />510 640 - 600730<br />600 - 680≥ 720|≤ 300<br /> 350≥ 260<br />≥ 450<br /> 450≥ 500<br />≥ 600<br /> 550≥ 690|45<br />20<br /> 10<br />> 7<br />> 54|80 - 110<br />125 - 155165<br />150 160 - 180190<br />180 - 210<br />200 - 230<br />≥ 220|0 x t<br />0 x t<br />0 x t<br />0 x t<br />1 x t|0 x t<br />0 x t<br />0 x t<br />1 x t<br />2 x t|500480
|230
|-
|CuSn1CrNiTiCuSn8|R 370<br />R 450<br />R 540<br />R 620600<br />R 660<br />R 740|370 - 450<br />450 - 550<br />540 - 620630<br />600 - 690<br />620 660 - 700750<br />≥ 740|≤ 300<br /> 350≥ 280<br />≥ 460<br /> 450≥ 530<br />≥ 620<br /> 520≥ 700|50<br /> 923<br />15<br /> 67<br />> 34|130 90 - 170120<br />135 - 175<br />160 170 - 200<br />180 190 - 220<br />210 - 240<br />≥ 230|0.5 x t<br />0 x t<br />0 x t<br />1 x t<br />3 2 x t|0.5 x t<br />2 0 x t<br />0 x t<br />1 x t<br />6 2 x t|530520|250240
|-
|CuNi1Co1SiCuSn3Zn9|R 800320<br />R 850|380<br /> 800R 430<br />R 510<br /> 850|> 760R 580<br />> 830R 660|320 - 380<br /> 4380 - 430<br />430 - 520<br /> 1|> 260510 - 600<br />> 275|0.5 x t580 - 690<br />1.5 x t≥ 660|1.5 x t≤ 230<br />2.5 x t|||-|CuCrSiTi|R 400≥ 200<br />R 460≥ 330<br />R 530|400 - 480≥ 430<br />460 - 540≥ 520<br />530 - ≥ 610|> 30025<br />> 37018<br />> 460|> 86<br />> 53<br />> 24|120 80 - 110<br />110 - 150140<br />140 - 170<br />150 160 - 190<br />180 - 210<br />≥ 200|0 x t<br />0.5 x t<br />0 x t<br />0 x t<br />1 x t|0 x t<br />0.5 x t<br />0 x t<br />1 x t<br />2 x t|400500|220210
|}
</figtable>
<sup>1)</sup> t: Strip thickness max. 0.5mm5 mm
<xr id="fig:Softening of CuZn36 50"/> <!--Fig. 5.9: --> Softening of CuZn36 after 3 hrs annealing after 50% cold working)
<xr id="fig:Phase diagram of the Cu-Sn system for the range of 0 – 30 wt% Sn"/> <!--Fig. 5.10: --> Phase diagram of the Cu-Sn system for the range of 0 – 30 wt% Sn)
<xr id="fig:Mechanical properties of tin bronze depending on the tin content (cold working 0 and 50%)"/> <!--Fig. 5.11: --> Mechanical properties of tin bronze depending on the tin content (cold working 0 and 50%)
<xr id="fig:Strain hardening of CuSn8 by cold working"/> <!--Fig. 5.12: --> Strain hardening of CuSn8 by cold working
<xr id="fig:Softening of CuSn8 after 3 hrs annealing after 50% cold working"/> <!--Fig. 5.13: --> Softening of CuSn8 after 3 hrs annealing after 50% cold working
<div class="multiple-images">
<div class="clear"></div>
====<!--5.1.4.3 -->Copper-Nickel-Zinc Alloys (German Silver)====
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 " α -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-->.
The relaxation behavior of Cu-Ni-Zn alloys is superior to the one for the tin bronzes. Additional advantages are the very good weldability, brazing
properties, and the high corrosion resistance of these copper-nickel-zinc alloys.
<figtable id="tab:tab5.11"><caption>'''<!--Table 5.11: -->Physical Properties of Copper-Nickel-Zinc Alloys'''</caption> {| class="twocolortable" style="text-align: left; font-size: 12px"|-!Material<br />Designation<br />EN UNS !Composition<br />[wt%]!Density<br />[g/cm<sup>3</sup>]!colspan="2" style="text-align:center"|Electrical<br />Conductivity!Electrical<br />Resistivity<br />[μΩ·cm]!Thermal<br />Conductivity<br />[W/(m·K)]!Coeff. of Linear<br />Thermal<br />Expansion<br />[10<sup>-6</sup>/K]!Modulus of<br />Elasticity<br />[GPa]!Softening Temperature<br />(approx. 10% loss in<br />strength)<br />[°C]!Melting<br />Temp Range<br />[°C]|-!!!![MS/m] ![% IACS]!!!!!!|-|CuNi12Zn24<br />CW403J<br />C75700|Cu 63- 66<br />Ni 11 - 13<br />Mn 0.5<br />Fe 0.3<br />Zn Rest|8.67|4.4|7|30|42|18|125|ca. 400|1020 - 1065|-|CuNi18Zn20<br />CW409J<br />C76400|Cu 60 - 63<br />Ni 17 - 19<br />Mn 0.5<br />Fe 0.3<br />Zn Rest|8.73|3.3|5|23|33|17.7|135|ca. 440|1055 - 1105|-|CuNi18Zn27<br />CW410J<br />C77000|Cu 53 - 56<br />Ni 17 - 19<br />Mn 0.5<br />Fe 0.3<br />Zn Rest|8.70|3.3|5|23|32|17.7|135|ca. 440|1050 - 1100|}</figtable>
<xr id="fig:Strain hardening of CuNi12Zn24 by cold working"/> <!--Fig. 5.15: --> Strain hardening of CuNi12Zn24 by cold working
<xr id="fig:Softening of CuNi12Zn24 after 3 hrs annealing after 50% cold working"/> <!--Fig. 5.16: --> Softening of CuNi12Zn24 after 3 hrs annealing after 50% cold working
<div class="multiple-images">
<figure id="fig:Copper rich region of the ternary copper-nickel-zinc phase diagram with indication of the more commonly available german silver materials">
[[File:Copper rich region of the termary copper nickel zinc phase diagram.jpg|right|thumb|Copper rich region of the ternary copper-nickel-zinc phase diagram with indication of the more commonly available german silver materials]]
</figure>
<figure id="fig:Strain hardening of CuNi12Zn24 by cold working">
<div class="clear"></div>
====<!--5.1.4.4 -->Copper-Silver-(Cadmium) Alloys (Silver Bronze)====
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 additionally 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"/> <!--(Tables 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.
Because of their good spring properties combined with high electrical conductivity silver bronzes are suitable for the use contact springs in relays
under higher current loads. Taking advantage of their high temperature stability they are also used as current carrying contacts in high voltage switchgear and as electrode material for resistance welding.
<figtable id="tab:tab5.13"><caption>'''<!--Table 5.13:-->Physical Properties of Selected Copper-Silver-(Cadmium) Alloys'''</caption> {| class="twocolortable" style="text-align: left; font-size: 12px"|-!Material<br />Designation<br />EN UNS !Composition<br />[wt%]!Density<br />[g/cm<sup>3</sup>]!colspan="2 teile" style="text-align:center"|Electrical<br />Conductivity!Electrical<br />Resistivity<br />[μΩ·cm]!Thermal<br />Conductivity<br />[W/(m·K)]!Coeff. of Linear<br />Thermal<br />Expansion<br />[10<sup>-6</sup>/K]!Modulus of<br />Elasticity<br />[GPa]!Softening Temperature<br />(approx. 10% loss in<br />strength)<br />[°C]!Melting<br />Temp Range<br />[°C]|-! !!![MS/m] ![% IACS]!!!!!!|-|CuAg2<br />not standardized<br />|Ag 2<br />Cu Rest<br />|9.0|49|85|2.0|330|17.5|123|ca. 330|1050 - 1075|-|CuAg2Cd1,5<br />not standardized<br />|Ag 2<br />Cd1,5<br />Cu Rest|9.0|43|74|2.3|260|17.8|121|ca. 350|970 - 1055|-|CuAg6<br />not standardized<br />|Ag 6<br />Cu Rest|9.2|38|66|2.4|270|17.5|120||960 - 1050|}</figtable>
<figtable id="tab:tab5.14"><caption>'''<!--Table 5.14: -->Mechanical Properties of Selected Copper-Silver-(Cadmium) Alloys''' </caption>
{| class="twocolortable" style="text-align: left; font-size: 12px"|-!Material!Hardness<br />Condition!Tensile Strength R<sub>m</sub><br />[MPa]!0,2 teile% Yield Strength<br />R<sub>p02</sub><br />[MPa]!Elongation<br />A<sub>50</sub><br />[%]!Vickers<br />Hardness<br />HV!Bend Radius<sup>1)</sup><br />perpendicular to<br />rolling direction!Bend Radius<sup>1)</sup><br />parallel to<br />rolling direction!Spring Bending<br />Limit σ<sub>FB</sub><br />[MPa]!Spring Fatigue<br />Limit σ<sub>BW</sub><br />[MPa]|-|CuAg2|R 280<br />R 380<br />R 450<br />R 550|280 - 380<br />380 - 460<br />450 - 570<br />≥ 550|≤ 180<br />≥ 300<br />≥ 420<br />≥ 500|30<br />6<br />3<br />1|50 - 110<br />100 - 140<br />130 - 165<br />≥ 160|0 x t<br />0 x t<br />1 x t|0 x t<br />0 x t<br />1 x t|400|190|-|CuAg2Cd1,5|R 300<br />R 380<br />R 480<br />R 600|300 - 380<br />380 - 490<br />480 - 620<br />≥ 600|≤ 190<br />≥ 310<br />≥ 440<br />≥ 550|30<br />8<br />3<br />1|55 - 110<br />100 - 145<br />130 - 170<br />≥ 160|0 x t<br />0 x t<br />1 x t|0 x t<br />0 x t<br />1 x t|440|220|-|CuAg6|R 320<br />R 400<br />R 500<br />R 650|320 - 400<br />400 - 510<br />500 - 660<br />≥ 650|≤ 210<br />≥ 330<br />≥ 460<br />≥ 610|30<br />6<br />3<br />1|70 - 120<br />110 - 150<br />145 - 175<br />≥ 175|0 x t<br />0 x t<br />1 x t|0 x t<br />0 x t<br />1 x t|460|230|}</figtable><sup>1)</sup> t: Strip thickness max. 0.5 mm
<div id="figures5">
<xr id="fig:Phase diagram of copper-silver for the range of 0 – 40 wt% silver"/><!--Fig. 5.17:--> Phase diagram of copper-silver for the range of 0 – 40 wt% silver <xr id="fig:Strain hardening of CuAg2 by cold working"/><!--Fig. 5.18:--> Strain hardening of CuAg2 by cold working <xr id="fig:Softening of CuAg2 after 1 hr annealing after 40% cold working"/> <!--Fig. 5.19: --> Softening of CuAg2 after 1 hr annealing after 40% cold working
<xr id="fig:Softening of CuAg2 after 1 hr annealing after 80% cold working"/> <!--Fig. 5.20: --> Softening of CuAg2 after 1 hr annealing after 80% cold working
</div>
<div class="multiple-images">
<figure id="fig:Phase diagram of copper-silver for the range of 0 – 40 wt% silver">
[[File:Phase diagram of copper silver.jpg|left|thumb|<caption>Phase diagram of copper-silver for the range of 0 – 40 wt% silver</caption>]]
</figure>
<figure id="fig:Strain hardening of CuAg2 by cold working">
[[File:Strain hardening of CuAg2 by cold working.jpg|rightleft|thumb|<caption>Strain hardening of CuAg2 by cold working</caption>]]
</figure>
<figure id="fig:Softening of CuAg2 after 1 hr annealing after 40% cold working">
[[File:Softening of CuAg2 40.jpg|rightleft|thumb|<caption>Softening of CuAg2 after 1 hr annealing after 40% cold working</caption>]]
</figure>
<figure id="fig:Softening of CuAg2 after 1 hr annealing after 80% cold working">
[[File:Softening of CuAg2 80.jpg|rightleft|thumb|<caption>Softening of CuAg2 after 1 hr annealing after 80% cold working</caption>]]
</figure>
</div>
==References==
[[Contact Carrier Materials#References|References]]
[[de:Naturharte_Kupfer-Legierungen]]
