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→5.1.6.1 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 the
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 treatmentsPhase_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 AlloysPhysical_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 Selected Copper-Beryllium Alloys"/> (Table 5.18) and [[#figures7|(Figs. 43 – 75)]](Figs. 5.29 - 5.31).
<div id="figures7">
<xr id="fig:Phase diagram of copperberyllium with temperature ranges for brazing and annealing treatmentsPhase_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
<div class="multiple-images">
<figure id="fig:Phase diagram of copperberyllium with temperature ranges for brazing and annealing treatmentsPhase_diagram_of_copperberyllium_with_temperature_ranges_for_ brazing_and_annealing_treatments">
[[File:Phase diagram of copper beryllium with temperature ranges.jpg|left|thumb|<caption>Phase diagram of copper- beryllium with temperature ranges for brazing and annealing treatments</caption>]]
</figure>
<figtable id="tab:Physical Properties of Selected Copper-Beryllium AlloysPPhysical_Properties_of_Selected_Copper_Beryllium_Alloys">
<caption>'''Table 5.17: Physical Properties of Selected Copper-Beryllium Alloys'''</caption>
