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→Copper-Silver-(Cadmium) Alloys (Silver Bronze)
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 ''(Tables <xr id="tab:Physical_Properties_of_ Selected_Copper_Zinc_Alloys"/><!--(Tab. 5.7 )--> and <xr id="tab:Mechanical_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_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"/><!--(Fig. 5.6)''-->).
<figtable id="tab:Physical_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"|-!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]!!!!!!|-|CuZn5<br />CW500L<br />C21000|Cu 94 - 96<br />Zn Rest|8.87|33|57|3.8|243|18.0|127||1055 - 1065|-|CuZn10<br />CW501L<br />C22000|Cu 89 - 91<br />Zn Rest|8.79|25|43|4.0|184|18.2|125||1030 - 1045|-|CuZn15<br />CW502L<br />C23000|Cu 84 - 86<br />Zn Rest|8.75|21|36|4.8|159|18.5|122|ca. 250|1005 - 1025|-|CuZn20<br />CW503L<br />C24000|Cu 79 - 81<br />Zn Rest|8.67|19|33|5.3|142|18.8|120|ca. 240|980 - 1000|-|CuZn30<br />CW505L<br />C26000|Cu 69 - 71<br />Zn Rest|8.53|16|28|6.3|124|19.8|114|ca. 230|910 - 940|-|CuZn37<br />CW508L<br />C27200|Cu 62 - 64<br />Zn Rest|8.45|15.5|27|6.5|121|20.2|110|ca. 220|900 - 920|-|CuZn23Al3Co<br />CW703R<br />C68800|Cu 73.5<br />Al 3.4<br />Co 0.4<br />Zn Rest|8.23|9.8|17|10.2|78|18.2|116|ca. 280|950 - 1000|}</figtable> <figtable id="tab:Mechanical_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"|-!Material!Hardness<br />Condition!Tensile Strength R<sub>m</sub><br />[MPa]!0,2% YieldStrength<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]|-|CuZn5|R 230<br />R 270<br />R 340|230 - 280<br />270 -350<br />340 - 440|≤ 130<br />≥ 200<br />≥ 280|36<br />12<br />4|45 - 90<br />70 - 120<br />110 - 160|0 x t<br />0 x t<br />|0 x t<br />0 x t<br />|250|130|-|CuZn10|R 240<br />R 280<br />R 350|240 - 290<br />280 - 360<br />350 - 450|≤ 140<br />≥ 200<br />≥ 290|36<br />13<br />4|50 - 100<br />80 - 130<br />110 - 160|0 x t<br />0 x t<br />|0 x t<br />0 x t<br />|260|140|-|CuZn15|R 300<br />R 350<br />R 410<br />R 480<br />R 550|300 - 370<br />350 - 420<br />410 - 490<br />480 - 560<br />≥ 550|≤ 150<br />≥ 270<br />≥ 360<br />≥ 420<br />≥ 480|16<br />8<br />3<br />1<br />|85 - 120<br />100 - 150<br />125 - 155<br />150 - 180<br />≥ 170|0 x t<br />0 x t<br />0 x t<br />1 x t<br />|0 x t<br />0 x t<br />1 x t<br />3 x t<br />|300|160|-|CuZn20|R 270<br />R 320<br />R 400<br />R 480|270 - 320<br />320 - 400<br />400 - 480<br />480 - 570|≤ 150<br />≥ 200<br />≥ 320<br />≥ 440|38<br />20<br />5<br />3|55 - 105<br />95 - 155<br />120 - 180<br />≥ 150|0 x t<br />0 x t<br />0 x t<br />|0 x t<br />0 x t<br />0 x t<br />|320|180|-|CuZn30|R 270<br />R 350<br />R 410<br />R 480|270 - 350<br />350 - 430<br />410 - 490<br />480 - 580|≤ 160<br />≥ 200<br />≥ 430<br />≥ 430|40<br />21<br />9<br />4|95 - 125<br />120 - 155<br />150 - 180<br />170 - 200|0 x t<br />0 x t<br />0 x t<br />1 x t|0 x t<br />1 x t<br />2 x t<br />3 x t|330|180|-|CuZn37|R 300<br />R 350<br />R 410<br />R 480<br />R 550|300 - 370<br />350 - 440<br />410 - 490<br />480 - 560<br />550 - 640|≤ 180<br />≥ 200<br />≥ 260<br />≥ 430<br />≥ 500|38<br />19<br />8<br />3<br />|55 - 105<br />95 - 155<br />120 - 190<br />≥ 150<br />≥ 170|0 x t<br />0 x t<br />0 x t<br />0.5 x t<br />1 x t|0 x t<br />0 x t<br />0 x t<br />1 x t<br />3 x t|350|190|-|CuZn23Al3Co|R 660<br />R 740<br />R 820|660 - 750<br />740 - 830<br />≥ 820|≥ 580<br />≥ 660<br />≥ 780|10<br />3<br />2|190 - 220<br />210 - 240<br />≥ 235|0 x t<br />1 x t<br />|0 x t<br />2 x t<br />|≥ 400|230|}</figtable><sup>1)</sup> t: Strip thickness max. 0.5 mm The main disadvantages of these alloys are with increasing zinc content , the also increasing tendency towards tension crack corrosion and the poorer stress relaxation properties , compared to other copper alloys.
One of the special brass alloys used as a contact carrier material is CuSn23Al3Co. This material exhibits significantly higher mechanical strength
than the standard brass alloys. Even so , this material is a naturally hardening alloy, a suitable heat treatment allows to further increase its strength. <div class="multiple-images">
====<!--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 electromechanical components , such as connectors, switches, and relays ''(Tables <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 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:Physical Properties of Copper-Tin Alloys"><caption>'''<!--Table 5.79: -->Physical Properties of Selected Copper-Zinc Tin 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]!!!!!!|-|CuSn4<br />CW450K<br />C51100|Sn 3.5 - 4.5<br />P 0.01 - 0.4<br />Cu Rest|8.85|12.0|20|8.3|118|18.0|120|ca. 260|960 - 1060|-|CuSn5<br />CW451K<br />C51000|Sn 4.5 - 5.5<br />P 0.01 - 0.4<br />Cu Rest|8.85|10.0|17|10.0|96|18.0|120|ca. 260|940 - 1050|-|CuSn6<br />CW452K<br />C51900|Sn 5.5 - 7.0<br />P 0.01 - 0.4<br />Cu Rest|8.80|9.0|15|11.1|75|18.5|118|ca. 280|910 - 1040|-|CuSn8<br />CW453K<br />C52100|Sn 7.5 - 8.5<br />P 0.01 - 0.4<br />Cu Rest|8.80|7.5|13|13.3|67|18.5|115|ca. 320|875 - 1025|-|CuSn3Zn9<br />CW454K<br />C42500|Zn 7.5 - 10<br />Sn 1.5 - 3.5<br />P 0.2<br />Ni 0.2<br />Cu Rest|8.75|12|28|6.2|120|18.4|126|ca. 250|900 - 1015|}</figtable>
<figtable id="tab:Mechanical Properties of Copper-Tin Alloys"><caption>'''<!--Table 5.910: Physical -->Mechanical Properties of Copper-Tin 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]|-|CuSn4|R 290<br />R 390<br />R 480<br />R 540<br />R 610|290 - 390<br />390 - 490<br />480 - 570<br />540 - 630<br />≥ 610|≤ 190<br />≥ 210<br />≥ 420<br />≥ 490<br />≥ 540|40<br />13<br />5<br />4<br />2|70 - 100<br />115 - 155<br />150 - 180<br />170 - 200<br />≥ 190|0 x t<br />0 x t<br />0 x t<br />0 x t|0 x t<br />0 x t<br />0 x t<br />1 x t|420|200|-|CuSn5|R 310<br />R 400<br />R 490<br />R 550<br />R 630<br />R 690|310 - 390<br />400 - 500<br />490 - 580<br />550 - 640<br />630 - 720<br />≥ 690|≤ 250<br />≥ 240<br />≥ 430<br />≥ 510<br />≥ 600<br />≥ 670|45<br />17<br />10<br />6<br />3|75 - 105<br />120 - 160<br />160 - 190<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|460|220|-|CuSn6|R 350<br />R 420<br />R 500<br />R 560<br />R 640<br />R 720|350 - 420<br />420 - 520<br />500 - 590<br />560 - 650<br />640 - 730<br />≥ 720|≤ 300<br />≥ 260<br />≥ 450<br />≥ 500<br />≥ 600<br />≥ 690|45<br />20<br />10<br />7<br />4|80 - 110<br />125 - 165<br />160 - 190<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|480|230|-|CuSn8|R 370<br />R 450<br />R 540<br />R 600<br />R 660<br />R 740|370 - 450<br />450 - 550<br />540 - 630<br />600 - 690<br />660 - 750<br />≥ 740|≤ 300<br />≥ 280<br />≥ 460<br />≥ 530<br />≥ 620<br />≥ 700|50<br />23<br />15<br />7<br />4|90 - 120<br />135 - 175<br />170 - 200<br />190 - 220<br />210 - 240<br />≥ 230|0 x t<br />0 x t<br />0 x t<br />1 x t<br />2 x t|0 x t<br />0 x t<br />0 x t<br />1 x t<br />2 x t|520|240|-|CuSn3Zn9|R 320<br />R 380<br />R 430<br />R 510<br />R 580<br />R 660|320 - 380<br />380 - 430<br />430 - 520<br />510 - 600<br />580 - 690<br />≥ 660|≤ 230<br />≥ 200<br />≥ 330<br />≥ 430<br />≥ 520<br />≥ 610|25<br />18<br />6<br />3<br />4|80 - 110<br />110 - 140<br />140 - 170<br />160 - 190<br />180 - 210<br />≥ 200|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|500|210|}</figtable><sup>1)</sup> t: Strip thickness max. 0.5 mm
<figure id====5"fig:Strain hardening of CuSn8 by cold working">[[File:Strain hardening of CuSn8 by cold working.1.4.3 Copper-Nickel-Zinc Alloys (German Silver)====jpg|left|thumb|<caption>Strain hardening of CuSn8 by cold working</caption>]]</figure>
<figure id="fig:Softening of CuSn8 after 3 hrs annealing after 50% cold working">[[File:Softening of CuSn8 50.jpg|left|thumb|<caption>Softening of CuSn8 after 3 hrs annealing after 50% cold working</caption>]]</figure></div><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 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]!!!!!!|-|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>
<div class====5.1.4.4 Copper-Silver"multiple-(Cadmium) Alloys (Silver Bronze)====images">
==References==
[[Contact Carrier Materials#References|References]]
[[de:Naturharte_Kupfer-Legierungen]]