Changes

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 ''(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 ''[[#figures7|(Figs. 43 – 75)]](Figs. 5.29 - 5.31)''.

<figure id="fig:Phase diagram of copperberyllium with temperature ranges for brazing and annealing treatments">Fig. 5.28:Phase diagram of copperberylliumwith temperature ranges for brazing and annealing treatments[[File:Phase diagram of copper beryllium with temperature ranges.jpg|right|thumb|Phase diagram of copper- beryllium with temperature ranges forbrazing and annealing treatments]]</figure>

<div id="figures7"><xr id="fig:Precipitation hardening of CuBe2 at 325°C after different cold working"/> Fig. 5.29:Precipitation hardeningof CuBe2 at 325°C afterdifferent cold working

<xr id="fig:Precipitation hardening of CuBe2 (soft) at 325°C"/> Fig. 5.30:Precipitationhardening of CuBe2(soft) at 325°C

<xr id="fig:Precipitation hardening of CuBe2 (half hard) at different annealing temperatures"/> Fig. 5.31:Precipitationhardening of CuBe2(half hard) at differentannealing temperatures</div>

Table 5<div class="multiple-images"><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|right|thumb|Precipitation hardening of Selected Copper-Beryllium Alloys (2 Teile!)CuBe2 at 325°C after different cold working]]</figure>

<figure id="fig:Precipitation hardening of CuBe2 (soft) at 325°C"> [[File:Precipitation hardening of CuBe2 (soft) at 325C.jpg|right|thumb|Precipitation hardening of CuBe2 (soft) at 325°C]]</figure> <figure id="fig:Precipitation hardening of CuBe2 (half hard) at different annealing temperatures"> [[File:Precipitation hardening of CuBe2 half hard.jpg|right|thumb|Precipitation hardening of CuBe2 (half hard) at different annealing temperatures]]</figure></div><div class="clear"></div> '''Table 5.17: Physical Properties of Selected Copper-Beryllium Alloys''' (2 Teile!) '''Table 5.18: Mechanical Properties of Selected Copper-Beryllium Alloys ''' (2 Teile!)

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 Figs. 5.33-5.35 ''(Tables 5.19 and 5.20)''.

<figure id="fig:Copper corner of the copper-chromium phase diagram for up to 0.8 wt% chromium">Fig. 5.32:Copper corner of the copper-chromium phase diagram for up to 0.8 wt% chromium[[File:Copper corner of the copper chromium phase diagram.jpg|right|thumb|Copper corner of the copper-chromiumphase diagram for up to 0.8 wt% chromium]] </figure>

Fig. 5.33:Softening of precipitation-hardened and subsequently cold worked CuCr1 after 4hrs annealing[[File:Softening of precipitation hardened and subsequently cold worked CuCr1.jpg|right|thumb|Softening of precipitation-hardenedand subsequently coldworked CuCr1 after4hrs annealing]]

Fig. 5.34 a:Electrical conductivity of precipitation hardened CuCr 0.6 as a function of annealing conditions[[File:Electrical conductivity of precipitation hardened CuCr 0.6.jpg|right|thumb|Electrical conductivity ofprecipitation hardenedCuCr 0.6 as a function ofannealing conditions]]

Fig. 5.34 b:Hardness of precipitation hardened CuCr 0.6 as a function of annealing conditions[[File:Hardness of precipitation hardened CuCr 0.6.jpg|right|thumb|Hardness ofprecipitation hardenedCuCr 0.6 as a functionof annealing conditions]]

Fig. 5.35:Electrical conductivity and hardness of precipitation hardened CuCr 0.6 after cold working[[File:Electrical conductivity and hardness of precipitation hardened CuCr 0.6.jpg|right|thumb|Electrical conductivityand hardness of precipitationhardened CuCr 0.6 aftercold working]]

'''Table 5.19: Physical Properties of Other Precipitation Hardening Copper Alloys ''' (2 Teile!)

'''Table 5.20: Mechanical Properties of Other Precipitation Hardening Copper Alloys'''

Fig. 5.36:Copper corner of the copperzirconiumfor 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]]

Fig. 5.37:Softening of CuCr1Zr after 1 hr annealing and after 90% cold working[[File:Softening of CuCr1Zr after 1hr annealing.jpg|right|thumb|Softening of CuCr1Zr after1 hr annealing and after 90%cold working]]