Besides the naturally hard copper materials precipitation hardening copper alloys play also an important role as carrier materials for electrical contacts. By means of a suitable heat treatment finely dispersed precipitations of a second phase can be achieved which increase the mechanical strength of these copper alloys significantly.  ====<!--5.1.6.1 -->Copper-Beryllium Alloys (Beryllium Bronze)====

phase diagram for CuBe shows, 2.4 wt% of Be are soluble in Cu at 780°C ''<xr id="fig:Phase_diagram_of_copperberyllium_with_temperature_ranges_for_brazing_and_annealing_treatments"/><!--(Fig. 5.28)''-->. In this temperature range annealed CuBe alloys are homogeneous(solution annealing). The homogeneous state can be frozen through rapid cooling to room temperature (quenching). Through a subsequent annealing at 325°C the desired precipitation hardening is achieved which results in a significant increase in mechanical strength and electrical conductivity of CuBe ''<xr id="tab:Physical_Properties_of_Selected_Copper_Beryllium_Alloys"/><!--(Table Tab. 5.17)''-->. The final strength and hardness values depend on the annealing temperature and time as well as on the initial degree of cold working ''<xr id="tab:Mechanical Properties of Selected Copper-Beryllium Alloys"/><!--(Table 5.18)'' --> and ''[[#figures7|(Figs. 43 – 75)]]<!--(Figs. 5.29 - 5.31)''. Fig-->. 5.28: Phase diagram of copperberyllium with temperature ranges for brazing and annealing treatments

<div id="figures7"> <xr id="fig:Phase_diagram_of_copperberyllium_with_temperature_ranges_for_brazing_and_annealing_treatments"/><!--Fig. 5.28:--> Phase diagram of copper- beryllium with temperature ranges for brazing and annealing treatments <xr id="fig:Precipitation_hardening_of_CuBe2_at_325°C_after_different_cold_working"/><!--Fig. 5.29: --> Precipitation hardening of CuBe2 at 325°C after different cold working[[File<xr id="fig:Precipitation_hardening_of_CuBe2_(soft)_at_325°C"/><!--Fig. 5.30:--> Precipitation hardening of CuBe2 (soft) at 325C325°C <xr id="fig:Precipitation_hardening_of_CuBe2_(half hard)_at_different_annealing_temperatures"/><!--Fig. 5.jpg|right|thumb|31:--> Precipitation hardening of CuBe2 (half hard) at 325°C after different cold working]]annealing temperatures</div> <div class="multiple-images">

Fig. 5.30<figure id="fig: Precipitation hardening of CuBe2 (soft) at 325°CPhase_diagram_of_copperberyllium_with_temperature_ranges_for_brazing_and_annealing_treatments">[[File:Precipitation hardening Phase diagram of CuBe2 (soft) at 325Ccopper beryllium with temperature ranges.jpg|rightleft|thumb|Precipitation hardening <caption>Phase diagram of CuBe2 (soft) at 325°Ccopper- beryllium with temperature ranges for brazing and annealing treatments</caption>]]</figure>

Fig. 5.31<figure id="fig: Precipitation hardening of CuBe2 (half hard) at different annealing temperaturesPrecipitation_hardening_of_CuBe2_at_325°C_after_different_cold_working"> [[File:Precipitation hardening of CuBe2 half hardat 325C.jpg|rightleft|thumb|<caption>Precipitation hardening of CuBe2 (half hard) at 325°C after different annealing temperaturescold working</caption>]]</figure>

'''Table 5<figure id="fig:Precipitation_hardening_of_CuBe2_(soft)_at_325°C"> [[File:Precipitation hardening of CuBe2 (soft) at 325C.17: Physical Properties jpg|left|thumb|<caption>Precipitation hardening of Selected Copper-Beryllium Alloys''' CuBe2 (2 Teile!soft)at 325°C</caption>]]</figure>

'''Table 5<figure id="fig:Precipitation_hardening_of_CuBe2_(half hard)_at_different_annealing_temperatures"> [[File:Precipitation hardening of CuBe2 half hard.18: Mechanical Properties jpg|left|thumb|<caption>Precipitation hardening of Selected Copper-Beryllium Alloys''' CuBe2 (2 Teile!half hard)at different annealing temperatures</caption>]]</figure></div><div class="clear"></div>

<figtable id====="tab:Physical_Properties_of_Selected_Copper_Beryllium_Alloys"><caption>'''<!--Table 5.1.6.2.1 17:-->Physical Properties of Selected Copper-Chromium Beryllium Alloys====='''</caption>

{| class="twocolortable" style="text-align: left; font-size: 12px"|-!Material<br />Designation<br />EN UNS !Composition<br />[wt%]!Density<br />[g/cm³]!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^-6/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]!!!!!!|-|CuBe1.7<br />CW100C<br />C17000|Be 1.6 - 1.8<br />Co 0.3<br />Ni 0.3<br />Cu Rest|8.4|8 - 9^a<br />12 - 13^b<br />11^c|14 - 16<br />21 - 22<br />19|11 - 12.5^a<br />7.7 - 8.3^b<br />9.1^c|110|17|125^a<br />135^b|ca. 380|890 - 1000|-|CuBe2<br />CW101C<br />C17200|Be 1.8 - 2.1<br />Co 0.3<br />Ni 0.3<br />Cu Rest|8.3|8 - 9^a<br />12 - 13^b<br />11^c|14 - 16<br />21 - 22<br />19|11 - 12.5^a<br />7.7 - 8.3^b<br />9.1^c|110|17|125^a<br />135^b|ca. 380|870 - 980|-|CuCo2Be<br />CW104C<br />C17500|Co 2.0 - 2.8<br />Be 0.4 - 0.7<br />Ni 0.3<br />Cu Rest|8.8|11 - 14^a<br />25 - 27^b<br />27 - 34^c|19 - 24<br />43 - 47<br />47 - 59|7.1 - 9.1^a<br />3.7 - 4.0^b<br />2.9^c|210|18|131^a<br />138^b|ca. 450|1030 - 1070|-|CuNi2Be<br />CW110C<br />C17510|Ni 1.4 - 2.2<br />Be 0.2 - 0.6<br />Co 0.3<br />Cu Rest|8.8|11 - 14^a<br />25 - 27^b<br />27 - 34^c|19 - 24<br />43 - 47<br />47 - 59|7.1 - 9.1^a<br />3.7 - 4.0^b<br />2.9^c|230|18|131^a<br />138^b|ca. 480|1060 - 1100|}</figtable> ^asolution annealed, and cold rolled<br /> ^bsolution annealed, cold rolled, and precipitation hardened<br /> ^csolution annealed, cold rolled, and precipitation hardened at mill (mill hardened)  <figtable id="tab:Mechanical Properties of Selected Copper-Beryllium Alloys"><caption>'''<!--Table 5.18:-->Mechanical Properties of Selected Copper-Beryllium Alloys'''</caption>  {| class="twocolortable" style="text-align: left; font-size: 12px"|-!Material!Hardness<br />Condition!Tensile Strength R_m<br />[MPa]!0,2% Yield Strength<br />R_p02<br />[MPa]!Elongation<br />A₅₀<br />[%]!Vickers<br />Hardness<br />HV!Bend Radius¹⁾<br />perpendicular to<br />rolling direction!Bend Radius¹⁾<br />parallel to<br />rolling direction!Spring Bending<br />Limit σ_FB<br />[MPa]!Spring Fatigue<br />Limit σ_BW<br />[MPa]|-|CuBe1,7|R 390^a<br />R 680^a<br />R 1030^b<br />R 1240^b<br />R 680^c<br />R 1100^c|380 -520<br />680 - 820<br />1030 - 1240<br />1240 - 1380<br />680 - 750<br />1100 - 1200|&ge; 180<br />&ge; 600<br />&ge; 900<br />&ge; 1070<br />&ge; 480<br />&ge; 930|35<br />2<br />3<br />1<br />18<br />3|80 - 135<br />210 - 250<br />330 - 380<br />360 - 420<br />220 - 350<br />330 - 370|0 x t<br />1 x t<br />1 x t<br /><br />1 x t<br />6 x t|0 x t<br />3 x t<br />1.5 x t<br /><br />1 x t<br />10 x t| <br /> <br />700<br />1000<br />390<br />790| <br /> <br />260<br />280<br /> <br />260|-|CuBe2|R 410^a<br />R 690^a<br />R 1140^b<br />R 1310^b<br />R 690^c<br />R 1200^c|410 -540<br />690 - 820<br />1140 - 1310<br />1310 - 1480<br />690 - 760<br />1200 - 1320|&ge; 190<br />&ge; 650<br />&ge; 1000<br />&ge; 1150<br />&ge; 480<br />&ge; 1030|35<br />2<br />3<br />1<br />18<br />3|90 - 140<br />215 - 260<br />350 - 400<br />380 - 450<br />220 - 250<br />360 - 410|0 x t<br />1 x t<br /> <br /> <br />1 x t<br />5 x t|0 x t<br />3 x t<br /> <br /> <br />1.5 x t<br />10 x t| <br /> <br />800<br />1040<br />400<br />900| <br /> <br />270<br />300<br /> <br />280|-|CuCo2Be<br />CuNi2Be|R 250^a<br />R 550^a<br />R 650^b<br />R 850^b<br />R 520^c|250 - 380<br />550 - 700<br />650 - 820<br />850 - 1000<br />520 - 620|&ge; 140<br />&ge; 450<br />&ge; 520<br />&ge; 750<br />&ge; 340|20<br />2<br />10<br />1<br />5|60 - 90<br />160 - 200<br />195 - 230<br />240 - 290<br />150 - 180|0 x t<br />3 x t<br />1 x t<br />3 x t<br />1 x t|0 x t<br /> <br />1 x t<br />3.5 x t<br />1 x t| <br /> <br />360<br />650<br />300| <br /> <br />220<br />250<br />210|}</figtable>¹⁾ t: Strip thickness max. 0.5 mm<br />^asolution annealed, and cold rolled<br /> ^bsolution annealed, cold rolled, and precipitation hardened<br /> ^csolution annealed, cold rolled, and precipitation hardened at mill (mill hardened) ====<!--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 ''<xr id="fig:Copper corner of the copper-chromium phase diagram for up to 0.8 wt% chromium"/><!--(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 [[#figures8|(Figs. 6 – 9)]]<!--Figs. 5.33-5.35 ''-->, <xr id="tab:Physical Properties of Other Precipitation Hardening Copper Alloys"/><!--(Tables 5.19 )--> and <xr id="tab:Mechanical Properties of Other Precipitation Hardening Copper Alloys"/><!--(Tab. 5.20)''-->.

<xr id="fig:Copper corner of the copper-chromium phase diagram for up to 0.8 wt% chromium"/><!--Fig. 5.3332: Softening --> Copper corner of precipitationthe copper-hardened and subsequently cold worked CuCr1 after 4hrs annealing[[File:Softening of precipitation hardened and subsequently cold worked CuCr1chromium phase diagram for up to 0.jpg|right|thumb|Softening of precipitation-hardened and subsequently cold worked CuCr1 after 4hrs annealing]]8 wt% chromium

Fig. 5.34 a<xr id="fig: Electrical conductivity Softening of precipitation hardened CuCr 0and subsequently cold worked CuCr1"/><!--Fig. 5.6 as a function of annealing conditions[[File33:Electrical conductivity of precipitation hardened CuCr 0.6.jpg|right|thumb|Electrical conductivity --> Softening of precipitation -hardened CuCr 0.6 as a function of and subsequently cold worked CuCr1 after 4hrs annealing conditions]]

Fig. 5.34 b<xr id="fig: Hardness Electrical conductivity of precipitation hardened CuCr 0.6 as "/><!--Fig. 5.34 a function of annealing conditions[[File:Hardness of precipitation hardened CuCr 0.6.jpg|right|thumb|Hardness --> Electrical conductivity of precipitation hardened CuCr 0.6 as a function of annealing conditions]]

Fig. 5.35<xr id="fig: Electrical conductivity and hardness Hardness of precipitation hardened CuCr 0.6 after cold working[[File"/><!--Fig. 5.34 b:Electrical conductivity and hardness --> Hardness of precipitation hardened CuCr 0.6.jpg|right|thumb|Electrical conductivity and hardness as a function of precipitation hardened CuCr 0.6 after cold working]]annealing conditions

'''Table <xr id="fig:Electrical conductivity and hardness of precipitation hardened CuCr 0.6"/><!--Fig. 5.1935: Physical Properties --> Electrical conductivity and hardness of Other Precipitation Hardening Copper Alloys''' (2 Teile!)precipitation hardened CuCr 0.6 after cold working</div>

<figure id=====5"fig:Copper corner of the copper-chromium phase diagram for up to 0.18 wt% chromium">[[File:Copper corner of the copper chromium phase diagram.6.2.2 jpg|left|thumb|<caption>Coppercorner of the copper-Zirconium Alloys=====chromium phase diagram for up to 0.8 wt% chromium</caption>]] </figure>

The solubility <figure id="fig:Softening of Zirconium in copper is 0.15 wt% Zr at the eutectic temperature precipitation hardened and subsequently cold worked CuCr1"> [[File:Softening of 980°C ''(Fig. 5.36)''. Copper-zirconium materials have a similar properties spectrum compared to the one for copper-chromium materialsprecipitation hardened and subsequently cold worked CuCr1. At room temperature the mechanical properties jpg|left|thumb|<caption>Softening of copperprecipitation-zirconium are less suitable than those of copper chromium, its temperature stability is however at least the same.hardened and subsequently cold worked CuCr1 after 4hrs annealing</caption>]]</figure>

<figure id=====5"fig:Electrical conductivity of precipitation hardened CuCr 0.16"> [[File:Electrical conductivity of precipitation hardened CuCr 0.6.2jpg|left|thumb|<caption>Electrical conductivity of precipitation hardened CuCr 0.3 Copper-Chromium-Zirconium Alloys=====6 as a function of annealing conditions</caption>]]</figure>

The earlier used <figure id="fig:Hardness of precipitation hardened CuCr 0.6"> [[File:Hardness of precipitation hardened CuCr and CuZr materials have been partially replaced over the years by the capitation hardening three materials alloy CuCr1Zr0. This material exhibits high mechanical strength at elevated temperatures and good oxidation resistance as well as high softening temperatures6. In its jpg|left|thumb|<caption>Hardness of precipitation hardened condition CuCr1Zr has also a high electrical conductivity (Bild 5CuCr 0.37). Their usage extends from mechanically and thermally highly stressed parts such 6 as contact tulips in high voltage switchgear to electrodes for resistance welding.a function of annealing conditions</caption>]]</figure>

Fig<figure id="fig:Electrical conductivity and hardness of precipitation hardened CuCr 0. 56"> [[File:Electrical conductivity and hardness of precipitation hardened CuCr 0.36:Copper corner 6.jpg|left|thumb|<caption>Electrical conductivity and hardness of the copperzirconiumfor up to precipitation hardened CuCr 0.5 wt%6 after cold working</caption>]]</figure></div>zirconium<div class="clear"></div>

 <figtable id="tab:Physical Properties of Other Precipitation Hardening Copper Alloys"><caption>'''<!--Table 5.19:-->Physical Properties of Other Precipitation Hardening Copper Alloys'''</caption>  {| class="twocolortable" style="text-align: left; font-size: 12px"|-!Material<br />Designation<br />EN UNS !Composition<br />[wt%]!Density<br />[g/cm³]!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^-6/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]!!!!!!|-|CuCr|Cr 0.3 - 1.2<br />Cu Rest|8.89|26^a<br />48^b|45^a<br />83^b|3.8^a<br />2.1^b|170^a<br />315^b|17|112|ca. 450|980 - 1080|-|CuZr|Zr 0.1 - 0.3<br />Cu Rest|8.9|35^a<br />52^b|60^a<br />90^b|2.9^a<br />1.9^b|340^a|16|135|ca. 500|1020 - 1080|-|CuCr1Zr<br />CW106C<br />C18150|Cr 0.5 - 1.2<br />Zr 0.03 - 0.3<br />Cu Rest|8.92|20^a<br />43^b|34^a<br />74^b|5.0^a<br />2.3^b|170^a<br />310 - 330^b|16|110^a<br />130^b|ca. 500|1070 - 1080|}</figtable> ^asolution annealed, and cold rolled<br /> ^bsolution annealed, cold rolled, and precipitation hardened<br />   <figtable id="tab:Mechanical Properties of Other Precipitation Hardening Copper Alloys"><caption>'''<!--Table 5.20:-->Mechanical Properties of Other Precipitation Hardening Copper Alloys'''</caption> <table class="twocolortable"><tr><th><p class="s16">Material</p></th><th><p class="s16">Hardness</p><p class="s16">Condi- tion</p></th><th><p class="s16">Tensile</p><p class="s16">Strength R<span class="s18">m</span></p><p class="s16">[MPa]</p></th><th><p class="s16">0,2% Yield</p><p class="s16">Strength R<span class="s18">p02</span></p><p class="s16">[MPa]</p></th><th><p class="s16">Elongation</p><p class="s16">A50</p><p class="s16">[%]</p></th><th><p class="s16">Vickers</p><p class="s16">Hardness</p><p class="s16">HV</p></th><th><p class="s16">Spring Bending</p><p class="s16">Limit <span class="s19">F</span><span class="s18">FB </span>[MPa]</p></th></tr><tr><td><p class="s16">CuCr</p></td><td><p class="s16">R 230<span class="s18">a</span></p><p class="s16">R 400<span class="s18">a </span>R 450<span class="s18">b </span>R 550<span class="s18">b</span></p></td><td><p class="s33">&gt;<span class="s16"> 230</span></p><p class="s33">&gt;<span class="s16"> 400</span></p><p class="s33">&gt;<span class="s16"> 450</span></p><p class="s33">&gt;<span class="s16"> 550</span></p></td><td><p class="s33">&gt;<span class="s16"> 80</span></p><p class="s33">&gt;<span class="s16"> 295</span></p><p class="s33">&gt;<span class="s16"> 325</span></p><p class="s33">&gt;<span class="s16"> 440</span></p></td><td><p class="s16">30</p><p class="s16">10</p><p class="s16">10</p><p class="s16">8</p></td><td><p class="s33">&gt;<span class="s16"> 55</span></p><p class="s33">&gt;<span class="s16"> 120</span></p><p class="s33">&gt;<span class="s16"> 130</span></p><p class="s33">&gt;<span class="s16"> 150</span></p></td><td><p class="s16">350</p></td></tr><tr><td><p class="s16">CuZr</p></td><td><p class="s16">R 260<span class="s18">a</span></p><p class="s16">R 370<span class="s18">a </span>R 400<span class="s18">b </span>R 420<span class="s18">b</span></p></td><td><p class="s33">&gt;<span class="s16"> 260</span></p><p class="s33">&gt;<span class="s16"> 370</span></p><p class="s33">&gt;<span class="s16"> 400</span></p><p class="s33">&gt;<span class="s16"> 420</span></p></td><td><p class="s33">&gt;<span class="s16"> 100</span></p><p class="s33">&gt;<span class="s16"> 270</span></p><p class="s33">&gt;<span class="s16"> 280</span></p><p class="s33">&gt;<span class="s16"> 400</span></p></td><td><p class="s16">35</p><p class="s16">12</p><p class="s16">12</p><p class="s16">10</p></td><td><p class="s33">&gt;<span class="s16"> 55</span></p><p class="s33">&gt;<span class="s16"> 100</span></p><p class="s33">&gt;<span class="s16"> 105</span></p><p class="s33">&gt;<span class="s16"> 115</span></p></td><td><p class="s16">280</p></td></tr><tr><td><p class="s16">CuCr1Zr</p></td><td><p class="s16">R 200<span class="s18">a</span></p><p class="s16">R 400<span class="s18">b</span></p><p class="s16">R 450<span class="s18">b</span></p></td><td><p class="s33">&gt;<span class="s16"> 200</span></p><p class="s33">&gt;<span class="s16"> 400</span></p><p class="s33">&gt;<span class="s16"> 450</span></p></td><td><p class="s33">&gt;<span class="s16"> 60</span></p><p class="s33">&gt;<span class="s16"> 210</span></p><p class="s33">&gt;<span class="s16"> 360</span></p></td><td><p class="s16">30</p><p class="s16">12</p><p class="s16">10</p></td><td><p class="s33">&gt;<span class="s16"> 70</span></p><p class="s33">&gt;<span class="s16"> 140</span></p><p class="s33">&gt;<span class="s16"> 155</span></p></td><td><p class="s16">420</p></td></tr></table></figtable> =====<!--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 <xr id="fig:Copper corner of the copper zirconium for up to 0.5-wt zirconium"/><!--(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. =====<!--5.1.6.2.3-->Copper-Chromium-Zirconium Alloys===== 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 <xr id="fig:Softening of CuCr1Zr after 1hr annealing"/><!--(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. <xr id="fig:Copper corner of the copper zirconium for up to 0.5-wt zirconium"/><!--Fig. 5.36:--> Copper corner of the copper- zirconium for up to 0.5 wt% zirconium <xr id="fig:Softening of CuCr1Zr after1hr annealing"/><!--Fig. 5.37:--> Softening of CuCr1Zr after 1 hr annealing and after 90% cold working <div class="multiple-images"><figure id="fig:Copper corner of the copper zirconium for up to 0.5-wt zirconium">[[File:Copper corner of the copper zirconium for up to 0.5-wt zirconium.jpg|right|thumb|Copper corner of the copper- zirconium for up to 0.5 wt% zirconium]] </figure> <figure id="fig:Softening of CuCr1Zr after 1hr annealing">[[File:Softening of CuCr1Zr after 1hr annealing.jpg|right|thumb|Softening of CuCr1Zr after 1 hr annealing and after 90%cold working]]</figure></div><div class="clear"></div>