Changes

=====5Besides the naturally hard copper materials, precipitation hardening copper alloys play also an important role as carrier materials for electrical contacts.1By means of a suitable heat treatment, finely dispersed precipitations of a second phase can be achieved, that increases the mechanical strength of these copper alloys significantly.6.1 Copper-Beryllium Alloys (Beryllium Bronze)=====

The cause for precipitation hardening of CuBe materials is the rapidly diminishing solubility of beryllium in copper as temperature decrease. As thephase diagram for CuBe shows, 2.4 wt% of Be are soluble in Cu at 780°C ''(Fig. ====<!--5.28)''1. In this temperature range annealed CuBe alloys are homogeneous(solution annealing)6. The homogeneous state can be frozen through rapid cooling to room temperature 1-->Copper-Beryllium Alloys (quenchingBeryllium Bronze). 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 ''(Table 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 ''(Table 5.18)'' and ''(Figs. 5.29 - 5.31)''.====

The cause for precipitation hardening of CuBe materials, is the rapidly diminishing solubility of beryllium in copper as temperature decreases. As thephase 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:Phase diagram Physical_Properties_of_Selected_Copper_Beryllium_Alloys"/><!--(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 copperberylliumwith temperature ranges forbrazing Selected Copper-Beryllium Alloys"/><!--(Table 5.18)--> and annealing treatments<xr id="fig:Precipitation_hardening_of_CuBe2_at_325°C_after_different_cold_working"/>, <xr id="fig:Precipitation_hardening_of_CuBe2_(soft)_at_325°C"/>, <xr id="fig:Precipitation_hardening_of_CuBe2_(half hard)_at_different_annealing_temperatures"/>).

Since Beryllium is rated as a carcinogen by the European regulation EU-67/548As precipitation hardening alloys CuBe materials, it has been tried to reach the application properties of the well established mainly CuBe2 and CuBe1.7 have gained broad usage as current carrying contact springs because of their outstanding mechanical properties. Besides these, CuCo2Be and CuNi2Be, which have medium mechanical strength and CuBe2 alloys with a lower Be contentrelatively high electricalconductivity, are also used as contact carrier materials. The development efforts for alternate After stamping and forming into desired contact configurations, these CuBe materials are then precipitation hardening hardened. CuBe alloys are available as semi-finished materials without toxic in a variety of cold work conditions. They can also be supplied and declaration requiring additive materialsused in the already precipitation hardened condition, for example CuNiCoSiwithout significant strength losses. In this case, are aimed the hardening was already performed at the replacement of CuBealloy producer.

FigSince Beryllium is rated as a carcinogen by the European regulation EU-67/548, it has been tried to reach the application properties of the well established CuBe1. 57 and CuBe2 alloys with a lower Be content.29:Precipitation Development efforts for alternative precipitation hardeningof CuBe2 at 325°C afterdifferent cold workingmaterials without toxic and declarable additives are underway, e.g. CuNiCoSi as a substitute for CuBe.

Fig. 5.31<figure id="fig:Phase_diagram_of_copperberyllium_with_temperature_ranges_for_brazing_and_annealing_treatments">Precipitationhardening [[File:Phase diagram of copper beryllium with temperature ranges.jpg|left|thumb|<caption>Phase diagram of CuBe2(half hard) at differentcopper- beryllium with temperature ranges for brazing and annealing treatments</caption>]]annealing temperatures</figure>

Table 5<figure id="fig:Precipitation_hardening_of_CuBe2_at_325°C_after_different_cold_working"> [[File:Precipitation hardening of CuBe2 at 325C.17: Physical Properties jpg|left|thumb|<caption>Precipitation hardening of Selected Copper-Beryllium Alloys (2 Teile!)CuBe2 at 325°C after different cold working</caption>]]</figure>

Table 5<figure id="fig:Precipitation_hardening_of_CuBe2_(soft)_at_325°C"> [[File:Precipitation hardening of CuBe2 (soft) at 325C.18: Mechanical Properties jpg|left|thumb|<caption>Precipitation hardening of Selected Copper-Beryllium Alloys CuBe2 (2 Teile!soft)at 325°C</caption>]]</figure>

<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>

As the phase diagram shows, copper{| 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[[#text-chromium has reference1|^{a similar hardening profile compared to CuBe ''(Fig}]]<br />12 - 13[[#text-reference2|^b]]<br />11[[#text-reference3|^c]]|14 - 16<br />21 - 22<br />19|11 - 12. 5[[#text-reference1|^a]]<br />7.32)''7 - 8. In the hardened stage CuCr has limitations to work hardening3[[#text-reference2|^b]]9. Compared to copper it has 1[[#text-reference3|^c]]|110|17|125[[#text-reference1|^{a better temperature stability with good electrical conductivity}]]<br />[[#text-reference2|^b]]|ca. 380|890 - 1000|-|CuBe2<br />CW101C<br />C17200|Be 1.8 - 2. Hardness and electrical conductivity as 1<br />Co 0.3<br />Ni 0.3<br />Cu Rest|8.3|8 - 9[[#text-reference1|^{a function of cold working and precipitation hardening conditions are illustrated in Figs}]]<br />12 - 13[[#text-reference2|^b]]<br />11[[#text-reference3|^c]]|14 - 16<br />21 - 22<br />19|11 - 12. 5[[#text-reference1|^a]]<br />7.7 - 8.333[[#text-5reference2|^b]]<br />9.1[[#text-reference3|^c]]|110|17|125[[#text-reference1|^a]]<br />135[[#text-reference2|^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[[#text-reference1|^a]]<br />25 - 27[[#text-reference2|^b]]<br />27 - 34[[#text-reference3|^c]]|19 - 24<br />43 - 47<br />47 - 59|7.1 - 9.1[[#text-reference1|^a]]<br />3.7 - 4.0[[#text-reference2|^b]]<br />2.9[[#text-reference3|^c]]|210|18|131[[#text-reference1|^a]]<br />138[[#text-reference2|^b]]|ca. 450|1030 - 1070|-|CuNi2Be<br />CW110C<br />C17510|Ni 1.4 - 2.2<br />Be 0.2 - 0.6<br />Co 0.35 ''(Tables 53<br />Cu Rest|8.8|11 - 14[[#text-reference1|^a]]<br />25 - 27[[#text-reference2|^b]]<br />27 - 34[[#text-reference3|^c]]|19 - 24<br />43 - 47<br />47 - 59|7.1 - 9.1[[#text-reference1|^a]]<br />3.7 - 4.0[[#text-reference2|^b]]<br />2.9[[#text-reference3|^c]]|230|18|131[[#text-reference1|^a]]<br />138[[#text-reference2|^b]]|ca. 480|1060 - 1100|}<div id="text-reference1">_a solution annealed, and 5.20cold rolled</div><div id="text-reference2">_b solution annealed, cold rolled, and precipitation hardened</div><div id="text-reference3">_c solution annealed, cold rolled, and precipitation hardened at mill (mill hardened)''.</div></figtable><br/><br/>

<figtable id="tab:Mechanical Properties of Selected 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 usedBeryllium Alloys"><caption>'''<!--Table 5.18:-->Mechanical Properties of Selected Copper-Beryllium Alloys'''</caption>

Fig{| 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 Radius[[#text-reference4|¹]]<br />perpendicular to<br />rolling direction!Bend Radius[[#text-reference4|¹]]<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[[#text-reference5|^a]]<br />R 680[[#text-reference5|^a]]<br />R 1030[[#text-reference6|^b]]<br />R 1240[[#text-reference6|^b]]<br />R 680[[#text-reference7|^c]]<br />R 1100[[#text-reference7|^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. 5x 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[[#text-reference5|^a]]<br />R 690[[#text-reference5|^a]]<br />R 1140[[#text-reference6|^b]]<br />R 1310[[#text-reference6|^b]]<br />R 690[[#text-reference7|^c]]<br />R 1200[[#text-reference7|^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 />1.32:5 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[[#text-reference5|^a]]<br />R 550[[#text-reference5|^a]]<br />R 650[[#text-reference6|^b]]<br />R 850[[#text-reference6|^b]]<br />R 520[[#text-reference7|^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 />5Copper corner of the copper|60 - 90<br />160 - 200<br />195 -chromium230<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 />210phase diagram for up to |}<div id="text-reference4">₁ t: Strip thickness max. 0.8 wt% chromium5 mm</div><div id="text-reference5">_a solution annealed, and cold rolled</div><div id="text-reference6">_b solution annealed, cold rolled, and precipitation hardened</div><div id="text-reference7">_c solution annealed, cold rolled, and precipitation hardened at mill (mill hardened)</div></figtable> <br/><br/>

Fig====<!--5.1. 56.33:Softening of precipitation2--hardenedand subsequently coldworked CuCr1 after4hrs annealing>Other Precipitation Hardening Copper Alloys====

Fig. =====<!--5.34 a:Electrical conductivity ofprecipitation hardenedCuCr 01.6 as a function ofannealing conditions.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. 5.34 b:Hardness ofprecipitation 32)-->). In the hardenedstage CuCr 0has limitations to work hardening. Compared to copper it has a better temperature stability with good electrical conductivity.6 Hardness and electrical conductivity as a functionof annealing cold working and precipitation hardening conditionsare illustrated in [[#figures8|(Figs. 6 – 9]]<!--Figs. 5.33-5.35--> and <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)-->).

FigCopper-chromium materials are especially suitable for use as electrodes for resistance welding. 5.35:Electrical conductivityDuring brazing the loss in hardness is limited, if low melting brazing alloys and hardness of precipitationhardened CuCr 0reasonably short heating times are used.6 aftercold working

Table 5<figure id="fig:Copper corner of the copper-chromium phase diagram for up to 0.208 wt% chromium">[[File: Mechanical Properties Copper corner of Other Precipitation Hardening the copper chromium phase diagram.jpg|left|thumb|<caption>Copper Alloyscorner of the copper-chromium phase diagram for up to 0.8 wt% chromium</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 0.2 Copper-Zirconium Alloys======6 as a function of annealing conditions</caption>]]</figure>

The solubility <figure id="fig:Hardness of Zirconium in copper is precipitation hardened CuCr 0.15 wt% Zr at the eutectic temperature 6"> [[File:Hardness of 980°C ''(Figprecipitation hardened CuCr 0. 56.36)''jpg|left|thumb|<caption>Hardness of precipitation hardened CuCr 0. Copper-zirconium materials have 6 as a similar properties spectrum compared to the one for copper-chromium materials. At room temperature the mechanical properties function of copper-zirconium are less suitable than those of copper chromium, its temperature stability is however at least the same.annealing conditions</caption>]]</figure>

<figure id======5"fig:Electrical conductivity and hardness of precipitation hardened CuCr 0.16"> [[File:Electrical conductivity and hardness of precipitation hardened CuCr 0.6.2jpg|left|thumb|<caption>Electrical conductivity and hardness of precipitation hardened CuCr 0.3 Copper-Chromium-Zirconium Alloys=====6 after cold working</caption>]]</figure></div><div class="clear"></div>

Fig. <figtable id="tab:Physical Properties of Other Precipitation Hardening Copper Alloys"><caption>'''<!--Table 5.3619:-->Physical Properties of Other Precipitation Hardening Copper corner of the copperzirconiumfor up to 0.5 wt%zirconiumAlloys'''</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[[#text-reference8|^a]]<br />48[[#text-reference9|^b]]|45[[#text-reference8|^a]]<br />83[[#text-reference9|^b]]|3.8[[#text-reference8|^a]]<br />2.1[[#text-reference9|^b]]|170[[#text-reference8|^a]]<br />315[[#text-reference9|^b]]|17|112|ca. 450|980 - 1080|-|CuZr|Zr 0.1 - 0.3<br />Cu Rest|8.9|35[[#text-reference8|^a]]<br />52[[#text-reference9|^b]]|60[[#text-reference8|^a]]<br />90[[#text-reference9|^b]]|2.9[[#text-reference8|^a]]<br />1.9[[#text-reference9|^b]]|340[[#text-reference8|^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[[#text-reference8|^a]]<br />43[[#text-reference9|^b]]|34[[#text-reference8|^a]]<br />74[[#text-reference9|^b]]|5.0[[#text-reference8|^a]]<br />2.3[[#text-reference9|^b]]|170[[#text-reference8|^a]]<br />310 - 330[[#text-reference9|^b]]|16|110[[#text-reference8|^a]]<br />130[[#text-reference9|^b]]|ca. 500|1070 - 1080|}<div id="text-reference8">_a solution annealed, and cold rolled</div><div id="text-reference9">_b solution annealed, cold rolled, and precipitation hardened</div></figtable><br /><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 or electrodes for resistance welding. <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|Figure 10: Copper corner of the copper- zirconium for up to 0.5 wt% zirconium]] </figure> <figure id="fig:Softening of CuCr1Zr after1hr annealing">[[File:Softening of CuCr1Zr after 1hr annealing.jpg|right|thumb|Figure 11: Softening of CuCr1Zr after 1 hr annealing and after 90%cold working]]</figure></div><div class="clear"></div>