Pure Copper

1. Oxygen almost does not dissolve in copper. When copper containing oxygen solidifies, oxygen precipitates as a EUTECTIC and distributes on the grain boundary of copper. When the oxygen content of as-cast copper is very low, the hypoeutectic, eutectic and hypereutectic of CU2O will appear with the increase of oxygen content. For example, trace oxygen can oxidize trace impurities such as Fe, SN and P in high purity copper, which can improve the conductivity of copper. Oxygen partially weakens the effect of SB and CD on copper conductivity, but does not change the effect of As, s, Se, Te and Bi on copper conductivity. P, CA, SI, Li, Be, AL, MG, Zn, NA, SR, B and so on can Be used as deoxidizers of copper, of which P is the most commonly used. When p content reaches 0.1% , it does not affect the mechanical properties of copper, but seriously reduces the conductivity of copper. For high conductivity copper, P content should not be more than 0.001% . On the one hand, CU2O has little effect on the properties of copper. On the other hand, Cu2o can react with impurities such As Bi, SB and As to form spherical particles with high melting point which are distributed in the grains, eliminates Grain Boundary Brittleness. When the oxygen content is between 0.016% and 0.036% , the tensile strength of copper increases with the increase of oxygen content, but the plasticity and fatigue limit of copper will decrease. When the oxygen content is between 0.003% ~ 0.008% , the iron content is between 0.06% ~ 2.09% , with the increase of the content of the two elements, the electrical conductivity and elongation of copper decrease obviously, but the tensile strength and fatigue strength increase obviously. When arsenic and Oxygen co-exist, the mechanical properties of copper have no obvious effect, but the conductivity of copper is obviously reduced. 

2. The solubility of hydrogen in liquid-solid and solid-state copper increases with the increase of temperature. Hydrogen forms intermittent solid solution in the solid copper, enhances the copper's hardness. Oxygen-containing copper annealing in hydrogen, hydrogen and copper in CU2O reaction, produce high-pressure steam, so that copper rupture, commonly known as "hydrogen disease. ". The occurrence and harm degree of hydrogen disease is related to temperature. At 150 °C, the oxygen-containing copper can be stored for 10 years without cracking due to the condensing state of Water Vapor, and can be stored for 1.5 years at 200 °C and only for 70 hours at 400 °C. DEOXYGENATED COPPER WITH MG or B does not develop hydrogen sickness. 

3. The solubility of sulfur in copper at room temperature is zero, and sulfur exists in copper as the dispersed particle of Cu2S, which reduces the conductivity and thermal conductivity of copper, but greatly reduces the plasticity of copper and improves the machinability of copper. 

4. Trace Selenium in selenium copper exists in the form of Cu2Se compound. The solubility of selenium in solid copper is very low, which has little effect on the conductivity and thermal conductivity of copper. 

5. Tellurium

The solubility of tellurium in solid copper is very small, and the existence of Cu2Te dispersion particle has little effect on the conductivity and thermal conductivity of copper, but it can improve the machinability of copper. Copper containing 0.06% ~ 0.70% te has been applied in industry and in quenching and processing state. Do not temper to avoid the precipitation of Cu2Te along grain boundary and make the material become brittle. Trace amounts (0.003%) of selenium and tellurium (0.0005% ~ 0.0030%) significantly reduced the solderability of copper.

 6. The maximum solubility of phosphorus in copper (714 °C eutectic temperature) is 1.75% , and it is almost zero at room temperature. The conductivity and thermal conductivity of copper are obviously reduced, but the mechanical properties and weldability of steel are well affected. Therefore, a certain amount of residual phosphorus is required in the dephosphorization of copper. Phosphorus can improve the fluidity of copper melt. The content of phosphorus in oxygen-free copper used for electric vacuum packaging should not be more than 0.0003% , otherwise the oxide film of Boride treatment is easy to peel off, which may cause the leakage of electronic tube. 

7.The effect of Si, MG and so on is similar to that of phosphorus. Kill. At eutectic temperature, the solubility of arsenic in copper can reach 6.77% . A small amount of arsenic can improve the processability of copper containing oxygen, but has little effect on the mechanical properties. As can react with CU2O in copper to form copper arsenate particles with high melting point, thus eliminating Cu + Cu2O eutectic at grain boundary and improving the plasticity of copper. Copper containing 0.15% ~ 0.50% arsenic can be used to make parts and components working in high temperature reduction atmosphere and low pressure feedwater heaters in power plants. 

8. When the EUTECTIC temperature is 645 °c, the solubility of antimony in copper can reach 9.5% and decrease rapidly with the decrease of temperature. Antimony reduces the corrosion resistance, electrical conductivity and thermal conductivity of copper. The SB content of copper for electrical purposes shall not be greater than 0.02% . Antimony can react with Cu2o in oxygen-containing copper to form spherical particles with high melting point and distribute in grains, which can eliminate Cu + Cu2O eutectic at grain boundaries and improve copper plasticity.

9. The solubility of Bismuth and Bismuth in copper is negligible, even at 800 °c the solubility is only 0.01% . At 270 °C, Bismuth and copper form a EUTECTIC, and Bismuth is distributed in the grain boundary as a thin film, which greatly reduces the processability of copper. Therefore, its content should not be greater than 0.002% . Bi has little effect on the thermal conductivity and electrical conductivity of copper. 0.7% ~ 1.0% Bi can be found in the contact copper of vacuum switch. Because it has high conductivity, and can prevent the switch from sticking, improve its working life and ensure safe operation. 

10. Lead is not solid-soluble in copper, but black particles are distributed in the EUTECTIC and exist in the grain boundary. PB has no significant effect on the electrical conductivity and thermal conductivity of copper, and can greatly improve the machinability of copper. Copper alloy containing 1.0% PB is used for machining high speed cutting parts. PB decreases the high temperature plasticity of Cu seriously, that is, the elongation and surface shrinkage decrease sharply, and the high temperature brittle zone also expands with the increase of CU content. Kill. The solubility of fe in cu reached 3.5% at 1050 °C, and the solubility of fe in cu decreased to 0.15% at 635 °C. The beneficial effect of iron is to refine copper grain, delay the recrystallization process of copper, and improve its strength and hardness. Iron reduces the plasticity, electrical conductivity, and thermal conductivity of copper. If iron is an independent phase in copper, then copper is ferromagnetic. Copper alloys containing 0.45% ~ 4.5% fe have high strength, good heat resistance, conductivity, weldability and processing formability. The lead frame must withstand temperatures of 350 °C for several minutes and temperatures of up to 500 °C for several seconds when assembling certain electronic devices. Therefore, C19400 and C19500 alloys containing iron are selected as lead frame materials because of their good conductivity, strength and oxidation resistance.

12. The solubility of silver in copper is 7.9% at 780 °C, but only about 0.1% at room temperature. However, the copper alloy containing 0.5% ag may still be a single solid solution in practical production. When the content of silver is small, the electrical conductivity and thermal conductivity of copper will not decrease much, and the effect on plasticity will be little. Therefore, high copper alloys containing 0.03% ~ 0.25% ag have become a kind of electrical materials with great practical value, such as C11300, C11400, C11500, C11600, C15500, etc. . Silver-bearing copper strip is a widely used material for automobile water tank. The Ag-containing C15500 alloy (99.75 cu-0.11 Ag-0.06p) is a good lead frame material with high conductivity, high strength and anti-softening ability. 

13. Beryllium is one of the effective deoxidizers for copper. However, beryllium is not used as deoxidizer because it is expensive and difficult to be added. The solid solution of trace beryllium as impurity has little effect on the mechanical and technological properties of copper, which makes the conductivity and thermal conductivity of copper decrease slightly, and improves the oxidation resistance of copper at high temperature obviously.

 14. As a impurity, aluminum solid solution in copper has no obvious effect on the mechanical and technological properties of copper, but decreases the conductivity, thermal conductivity, brazing and tin-plating properties of copper, and improves the oxygen resistance of copper. 

15. At the EUTECTIC temperature of 485 °c, the solid solubility of magnesium in copper is 0.61% and decreases rapidly with the decrease of temperature, so the alloy with high magnesium content (2.5% ~ 3.5%) has precipitation hardening effect. The applied Cu-Mg alloy contains less than 1% MG, such as 0.3% ー1.0% MG copper alloy used for processing conductive wire. These alloys have no ageing effect and can only be strengthened by cold working. Trace magnesium can decrease the electrical conductivity of copper, improve the oxidation resistance of copper at high temperature, and also deoxidize copper.

16. Lithium, Boron, manganese and calcium all have the deoxidization effect on copper. As an impurity, lithium can form a high melting point compound with bismuth and other impurities in copper, which is dispersed in the crystal grain in a fine state. The residual 0.005% ~ 0.015% B as copper deoxidizer can refine the copper grain and improve the mechanical and technological properties of copper. Manganese can be used as a deoxidizer for copper. The manganese deoxidizes copper containing 0.1% ~ 0.3% MN, which is solid-soluble in copper. On the one hand, the softening temperature of copper is increased, on the other hand, it is beneficial to the mechanical and technological properties of copper. Calcium is almost insoluble in copper. As an impurity, calcium can form a high melting point compound with impurity Bi, which is distributed uniformly in the crystal grain in the form of particle.

17.Kill. Rare-earth elements rare-earth elements generally do not dissolve in copper, but a small amount of rare-earth metals added, either alone or in a mixed form, is beneficial to the mechanical properties of copper and has little effect on its electrical conductivity. These elements can form high-melting-point compounds with lead and bismuth in copper. The fine spherical particles are distributed in the grains to refine the grains and improve the high-temperature plasticity of the steel. The addition of 0.008% mixed rare earth to copper can significantly improve the technological properties of copper. The mechanical properties, electrical conductivity and softening temperature of copper alloy containing 0.01% ー0.15% La are better than those of cu-0.15 AG alloy.

18.Kill. Refractory metals and other metals such as tungsten, molybdenum, niobium, uranium and plutonium hardly dissolve in solid solution in copper, while a small amount of elements such as titanium, zirconium, chromium and cobalt dissolve in copper, neutralizing the harmful effects of some fusible impurities is beneficial to improving high temperature plasticity. Copper alloys containing small amounts of zirconium (CL5000, C15100, C18100) , cobalt (C17110, C17500) , chromium (C18400, C18200, C18500) have been used in industry and become good electrical materials.

Brass 

1. The melting of iron in solid copper is very small, and the iron-rich phase particles are distributed in the matrix, which can refine the grains. The addition of 0.3% ~ 0.6% fe to H60 brass has a strong grain refinement effect, but the iron content of the magnetic-resistant copper should be less than 0.3% . The impurity iron has no obvious effect on the mechanical properties of brass. 

2. Lead and Bismuth lead and bismuth are harmful impurities in brass, and bismuth is more harmful than lead. Lead particles exist in the fusible eutectic at the grain boundary. If the lead content of brass is more than 0.03% , it will appear hot embrittlement, which has no obvious effect on the cold workability. Lead has no significant effect on the processability of dual-phase brass, and its allowable content can be slightly higher. Bismuth is distributed on the grain boundary as a continuous brittle film in brass, which makes the brass brittle during cold and hot processing. If the lead and bismuth content of cold-rolled brass exceeds the allowable limit, if the heating speed is too fast during the annealing process, "fire crack" will occur, that is, sudden burst. Brasses containing lead and bismuth can be eliminated by adding small amounts of elements such as zirconium to form high-melting-point compounds.

 3. The solubility of SB in copper decreases sharply with the decrease of temperature. When the content of SB is less than 0.1% , CU2SB will be formed and distributed in the grain boundary as a network, which makes the cold working property of brass decrease greatly. Antimony also contributes to the hot embrittlement of copper alloys. The high melting point compound LI3SB can be formed by adding trace lithium into brass, and the fine particles are distributed in the crystal grains, thus eliminating the disadvantageous effect of antimony. Because antimony has a higher melting degree in copper at high temperature, the cold working properties of antimony-bearing brass can be improved by solid solution treatment.

 4. Phosphorus in copper solid solubility is very small, a small amount of phosphorus grain refining effect, improve the mechanical properties of brass. When the phosphorus content of brass is more than 0.05% , the brittle phase Cu3P will be formed and the processing property of brass will be reduced. The recrystallization temperature of brass was increased by P, and the recrystallization grain size was not uniform. 

5. The solubility of arsenic in brass at room temperature is less than 0.01% , and the brittle phase compound Cu3As is formed when the content of arsenic is high. The corrosion resistance of brass containing 0.02% ~ 0.05% as can be improved without dezincification.

Bronze

 1. Tin Bronze 

(1) phosphorus content of tin bronze is generally not more than 0.45% . When the phosphorus content is more than 0.5% , the eutectic-peritectic reaction l + something + Cu3P will occur at 637 °C, which will lead to hot embrittlement. When the phosphorus content of the alloy is more than 0.3% , the eutectic of copper and copper phosphide (Cu3P) will appear in the microstructure. Phosphorus is an effective deoxidizer for copper alloy, which can improve the fluidity of tin bronze. The disadvantage is to increase the reverse segregation of the INGOT. The grain size before cold working and the low temperature annealing (180 ~ 300 °C) after cold working have great influence on the Mechanical Properties of sn-p bronze. When the grain size is small, the strength, hardness, elastic modulus and fatigue strength of the material are higher than those of the coarse grain material, but the plasticity is slightly lower. The strength, plasticity, elastic limit and elastic modulus of sn-p bronze annealed at 200 ~ 260 °C for 1 ~ 2 h were increased, and the elastic stability was also improved. 

(2) zinc is one of the alloy elements of Tin Bronze. The solubility of zinc in the solid solution of tin bronze is high. Therefore, Cu-Sn-Zn bronze is a single-phase solid solution. Zn improves the fluidity of the alloy, reduces the crystallization temperature range and reduces reverse segregation, but has no significant effect on its microstructure and properties. The zinc content in the processed tin bronze is generally not more than 5% . 

(3) PB is not more than 5% in tin bronze, it is not solid-soluble in phase, exists in Free State, and is distributed between Dendrites as black particles, but its distribution is not uniform. PB can reduce the friction coefficient of tin bronze, improve the wear resistance and machinability, but slightly reduce the mechanical properties of the alloy.

 (4) Fe is an impurity of tin bronze, its maximum content is 0.05% , which can refine grain, delay recrystallization and improve strength and hardness. But the content must not exceed the limit value, otherwise it will form too much iron-rich phase, reduce the corrosion resistance and process properties of the alloy. 

(5) MN is one of the harmful impurities in tin bronze. The content of MN should be strictly controlled and not more than 0.002% . Manganese oxidizes easily to form oxide, which reduces the fluidity of the Alloy Melt and distributes on the grain boundary after solidification, weakening the intercrystalline bonding and making the strength decrease. 

(6) Ti can form TiSn with Sn and dissolve in cu, which can enhance the hardness and softening temperature of tin bronze after annealing. The bronze alloys containing 0.20% ー0.75% TI and 5% sn can reach the peak hardness after solution treatment at 800 °C for 1 H and aging at 450 °C for 1 H.

(7) beryllium Be can form intermetallic compound with SN, which increases the strength of the alloy. The maximum hardness of cu-4.5% sn-1.0% be bronze aged at 325 °C after quenching. 

(8) the contents of AL, MG and MG IN SN bronze should not be more than 0.002% , and the contents of Mg should be strictly controlled, because their oxides will reduce the strength and melt fluidity of the alloy. Some tin bronze containing AL and MG has been developed abroad, which not only has high strength but also good corrosion resistance. For example, Cu-5Sn-7Al alloy has high corrosion resistance and strength, the strength of CU-5SN-LMG TIN bronze after aging treatment is up to 900 MPA, 30 HRC, and the conductivity is 30% ~ 35% IACS. It can be used to make components with high strength, high corrosion resistance and good conductivity. 

(9) SI is one of the harmful impurities of tin bronze. Si is soluble in the phase, which is beneficial to the mechanical properties of the alloy. If it remains in the Ingot, it will damage its strength. The maximum content of SI is 0.002% .

 (10) antimony, Bismuth, antimony and bismuth are harmful impurity elements of tin bronze, and their permitted maximum content is 0.002% . None of them are solid soluble in the phase. 

(11) zirconium, niobium and Boron are hardly solid-soluble in the phase, and trace Zr, NB and B can refine the grains. Therefore, it is beneficial to the mechanical properties and pressure processing properties of tin bronze.

2. Al-bronze 

(1) Fe can be dissolved in Cu-Al alloy solid solution in a small amount, but in excess it will form needle-like FEAL3, which will reduce the mechanical properties and corrosion resistance of alloy. Therefore, the FE content in the alloy should not exceed 5% . If the content of NI, MN AND AL in the alloy increases, the solubility of Fe in solid solution will decrease further. Iron can slow down the atomic diffusion rate and increase the phase stability of al-bronze, so it can restrain the self-annealing phenomenon and reduce the Brittleness of al-bronze. Proper amount of iron can refine the casting and recrystallizing grains of aluminum bronze and improve the mechanical properties. Adding 0.5% ~ 1.0% fe can obviously refine the grains.

 (2) nickel has a certain solid solubility in Cu-Al alloy. When the NI content exceeds the maximum solid solubility, a k-phase NiAl is formed. On the one hand, Ni increases the EUTECTOID transition temperature of al-bronze, on the other hand, it makes the composition of the eutectoid point move towards the direction of heating up, and also can change the phase morphology. When the NI content is low, the phase is needle-like, and when the NI content is 3% , it turns into flake. When MN is added to Cu-Al-Ni Alloy, the eutectoid transformation tends to form granular structure. Ni can significantly improve the strength, hardness, thermal stability and corrosion resistance of aluminum bronze. cu-al-Ni-fe alloy containing a certain amount of NI can be aged directly without solution treatment and quenching after hot working. Better comprehensive properties can be obtained by adding Ni and Fe into aluminum bronze. In Cu-A1-Ni-Fe alloy, the phase morphology has a great influence on its mechanical properties. The optimum ratio of NI TO FE IS 0.9 ~ 1.1. 

(3) MN has higher solubility in Cu-Al alloy solid solution, but lower solubility in Al.. Manganese can stabilize the phase decomposition, decrease the starting temperature of phase transformation and delay the eutectoid transformation. The MN content in aluminum bronze does not exceed the maximum solubility limit, which is beneficial to the mechanical properties and corrosion resistance of the alloy and has good formability. The binary aluminum bronze containing 0.3% ー0.5% MN has good hot workability and the tendency of cracking during hot rolling is remarkably reduced. The performance of the alloy is improved by adding a certain amount of Fe to the AL bronze containing MN, because Fe can refine the grains, but Fe can weaken the effect of MN on phase stabilization. 

(4) the addition of SN and cr-al bronze ≤0.2% sn can improve the stress corrosion cracking resistance of the alloy in steam and slightly acidic atmosphere. Chromium can improve the mechanical properties of Binary Cu-Al alloy, inhibit grain growth and increase the hardness of annealed material.

 (5) zn and si-zn are dissolved in Cu-Al alloy and the phase region is enlarged. However, Zn can decrease the fe-rich phase particles of Cu-Al-Ni-Fe alloy, and decrease the wear resistance of Cu-Al-Ni-Fe alloy. The maximum content of impurity zinc in aluminum bronze is 1.0% . Silicon is the impurity of aluminum bronze, its content must not exceed 0.2% , for most aluminum bronze must not exceed 0.1% , otherwise the mechanical properties and technological properties of the alloy will be reduced, but the machinability of the alloy will be improved. 

(6) the elements of P, S, as, SB and bi are harmful impurities of al-bronze. The reduction of mechanical properties, Technological Properties and other properties of the alloy should be strictly controlled within the standard range.

3. Silicon Bronze

 (1) manganese is beneficial to the mechanical properties, corrosion resistance and technological properties of silicon bronze. When the alloy containing less than 3% SI and 1% MN is cooled below 450 °C, the brittle phase MN2SI will be precipitated, but there is little strengthening effect. The higher the SI content of the alloy, the more the precipitated MN2SI and the greater the tendency of self-cracking. The self-cracking phenomenon can be eliminated by low temperature annealing with silicon content under 3% . 

(2) Ni-containing silicon bronze has good mechanical properties, corrosion resistance and electrical conductivity. Ni and SI can form compound Ni2si, and the solubility of Ni in solid solution is 9% at 1025 °C, but almost zero at room temperature. Therefore, when the ratio of Ni to SI in the alloy is 4:1, Ni2si can be completely formed, which has strong aging hardening effect and makes the alloy have good comprehensive properties. When the NI/SI ratio in the alloy is less than 4, it has high strength and hardness, but its electrical conductivity and plasticity will decrease, which is not good for pressure machining. The properties of Cu-Si-Ni alloy can be improved by adding a small amount of (0.1% ~ 0.4%) MN, because MN has both deoxidation effect and solution strengthening effect. 

(3) CR and Ni have similar effect, and can form solid-soluble chromium silicide, but have no effect of age hardening, which is one of the harmful impurities of silicon bronze. 

(4) cobalt and silicon can form solid-soluble Co2si, and the solubility decreases with the decrease of temperature, which has a certain aging strengthening effect. The quenching temperature is 1000 ~ 1050 °C, the aging temperature is 500 ~ 550 °C. Alloys containing a small amount of cobalt have been used. C66400, etc. . 

(5) zinc can dissolve more in Cu-Si alloy, improve the strength and hardness of the alloy, narrow the solidification temperature range, improve the fluidity of the alloy and improve its casting performance. CU-3.5 SI-3ZN-1.5 FE bronze is used in the manufacture of high temperature bushings. 

(6) although the solubility of Fe in solid solution decreases with the decrease of temperature, the solubility of Fe in solid solution is almost zero at room temperature. The effect of time-hardening is negligible. The FE content in Cu-Si alloy should not be more than 0.3% . Otherwise, a separate phase is formed and the corrosion resistance of the alloy is greatly reduced.

 (7) Ti can refine the grain size of silicon bronze, strengthen the aging hardening effect of Cu-Si alloy, and improve the strength and hardness of the material. (8) lead, aluminum, bismuth, arsenic, antimony, sulfur and phosphorus are harmful impurities in silicon bronze, which should be strictly controlled. Although PB can improve the wear resistance and machinability of the alloy, it can cause hot cracking. Aluminum is good for the strength and hardness of silicon bronze, but it makes the weldability worse.

4. Manganese bronze processing manganese bronze is a Cu-Mn binary alloy, which has high mechanical properties, corrosion resistance, heat resistance, cold, hot pressure processing, mostly used to manufacture parts working at high temperature. Mn can increase the recrystallization temperature of copper (150 ~ 200 °C) because of its high solid solution strengthening effect. Contains 16.3at. An ordered phase of Cu5Mn was formed at 400 °C in a copper alloy containing 0.5% MN cubic crystal system. Contains 25.0at. Cu3mn, an ordered phase of cubic crystal system, was formed at 450 °C in a copper alloy containing 0. When MN increases the hardness and strength of the alloy, the elongation increases with the increase of MN content at the beginning, and reaches the maximum value at 4% ~ 5% MN, then decreases, but has little change.

 (1) Zn has a great solubility in Cu-Mn alloy and has a certain effect of solution strengthening. 

(2) Ni can be dissolved in the solid solution of Cu-Mn alloy, which can enhance the corrosion resistance of the alloy. Cu-20mn-20ni alloy is a kind of aging hardening copper alloy. The mechanical properties of the hard material are tensile strength 1200MPa ~ 1300MPA, yield strength 1150MPa ~ 1250MPA, ELONGATION 1% ~ 4% , vickers hardness 370 ~ 410, elastic modulus 157GPa.

 (3) SN is one of the impurity elements in mn-bronze, its maximum content is 0.1% , soluble in Cu-Mn solid solution, Sn enlarges the solidification temperature range of mn-bronze. 

(4) the elements of AL, as, SI, SB, PB, P, s, fe and bi are impurities of manganese bronze, and the contents should be controlled within the standard range. The 56Cu-42Mn alloy containing 2% AL is a heat-treatable strengthened alloy, after solution treatment and aging, its strength is almost equal to that of structural steel, and its shock absorption capacity is very high, about 30% higher than that of gray iron, has been used to manufacture Shim, gear, saw blade and other shock absorption parts. 

(5) chromium bronze and cadmium bronze CR and CD can form solid solution with copper, and their solid solubility decreases significantly with the decrease of temperature, so they have precipitation hardening effect. These two kinds of bronze have high strength and hardness, wear resistance, heat resistance, high electrical conductivity and thermal conductivity, and good processing and forming properties. Cadmium is a harmful element to human body. When smelting, we should pay attention to protect the harm of its vapor to human body. The aging hardening effect of CU-CD alloy with low CD content is very small and has no practical production significance.

 (6) aluminum and magnesium AL and Mg can be used as alloying elements of chromium bronze. They can form a thin and dense oxide film on the surface of CU-CR alloy, which can be tightly bonded with the base metal, thus improving the high temperature oxidation resistance and heat resistance of the alloy. However, the content of AL and MG in the alloy is usually less than 0.3% . 

(7) tin and Ti-cr bronze can form the TISN intermetallic compound with age hardening effect, which is beneficial to the strength, hardness and heat resistance of the alloy. The conductive materials containing 0.3% ~ 0.5% CR, 0.15% ~ 0.25% sn and 0.05% ~ 0.12% ti are suitable for long-term use at 250 °C.

(8) Cr2zr, a Cu-soluble compound, is formed between Zr and CR, and its solubility decreases with the decrease of temperature, which increases the strength, hardness and heat resistance of the alloy, and has little effect on the electrical conductivity of the alloy.  Hafnium acts similarly to Zr in this type of bronze and forms a Hafnium-copper compound with some time-hardening effect with Cu. The strength of CU-0.6CR alloy after aging increases with the increase of Hafnium content, but the electrical conductivity decreases with the increase of Hafnium content. The bronze containing 0.6% CR and 0.2% ~ 0.6% HF, aged at 400 ~ 450 °C for 3 ~ 20 H, has both high mechanical properties and good electrical conductivity. Its tensile strength is more than 600 MPA and its electrical conductivity is 80% IACS. 

(9) Zinc and silver-zinc can be dissolved in the solid solution of chromium-bronze, which can improve the strength of the alloy, but has little effect on its conductivity. The addition of about 0.2% AG to cr-bronze can significantly increase the softening temperature of the alloy on the one hand, but does not reduce the electrical conductivity of the alloy on the other hand. 

(10) chromium is a beneficial micronutrient of cadmium bronze. A small amount of chromium (0.35% ~ 0.65%) has a significant beneficial effect on its aging strengthening effect. 

(11) the elements of iron, lead, bismuth, arsenic and phosphorus are harmful impurities of these two kinds of bronze, which should be strictly controlled and should not exceed the maximum standard.

5. At the EUTECTIC temperature of 966 °C, the limiting solubility of zirconium in copper is only 0.15% , but decreases rapidly with the decrease of temperature. Therefore, zirconium bronze has time-hardening effect and the strengthening phase is (Cu5Zr or Cu3zr) . Zirconium bronze has high conductivity, thermal conductivity and heat resistance, and has good creep resistance. Under 400 °C, the strength of Zircon bronze is equal to that of Zircon bronze, but the conductivity and plasticity of Zircon bronze are higher than that of Zircon bronze. Zirconium can significantly improve the recrystallization temperature of copper alloy, and its effect is greater than other elements. Cr2zr, a solid-soluble compound, can be found in zirconium bronze containing a small amount of CR, which has a dense hexagonal lattice at high temperature and a cubic crystal system at low temperature. CU-0.3 ZR-0.34CR alloy has obvious age strengthening effect, because it contains about 0.64% cr2zr. Because of the different contents of Zr and CR in Cu-Zr-Cr alloy, Cr2Zr was separated from the solid solution or the precipitated phase was strengthened with Cr2Zr. Arsenic can form Zr-As compound with Zr. As can increase the EUTECTIC temperature of Cu-Zr alloy to 1000 ~ 1020 °C, increase the solubility of Zr at that temperature and decrease the solubility at low temperature, refine the grains of lead bronze, and restrain the grain growth of Cu-Zr alloy during heating. Antimony, tin, lead, sulfur, iron, bismuth, nickel and other elements are harmful impurities of zirconium bronze, should not exceed the limit value specified in the standard. 6. The normal beryllium content in beryllium bronze processed is 0.20% ~ 2.00% , generally 0.2% ~ 2.7% co or less than 2.2% NI. Beryllium bronze is further divided into two categories: 1 High Strength Alloys, such as C17200, C17000; 2 high conductivity alloys, the beryllium content is low, usually not more than 0.7% , such as C17500, C17510, C17410. Beryllium levels approaching 12 at. % of the high-strength alloys are golden, while the high-conductivity beryllium bronze with low beryllium content is reddish or sandy gold. 

(1) nickel and cobalt nickel and cobalt are alloying elements of beryllium bronze. Ni and Be form an ordered cubic crystal system compound Nibe, which has a hardness of up to 610 MPA. NIBE is soluble in solid solution and has a maximum solubility of 3.25% (0.42% be, 2.83% ni) at a total temperature of 1030 °C. The solubility of NiBe decreases significantly with decreasing temperature. Therefore, this type of alloy has an obvious age hardening effect. The addition of 0.2% ~ 0.5% NI to Cu-Be alloy can delay the recrystallization process, retard the grain growth, greatly slow down the phase transformation process during cooling and inhibit the grain boundary reaction during aging, therefore, a small amount of Ni can further improve the mechanical properties of beryllium bronze after aging. However, when industrial beryllium bronze contains a small amount of Ni, a hard and brittle 1-phase appears, which reduces the fatigue strength, elastic hysteresis and elastic stability of the alloy. Therefore, both the number of phase 1 and its distribution should be controlled. High conductivity bronze plating often contains a certain amount of Co.. It is associated with the formation of compounds CoBe and CO5BE21. CoBe is a cubic crystal system with a microhardness of 443 MPA. The solubility of CoBe in solid solution decreases with the decrease of temperature, and the maximum solubility of CoBe at eutectic temperature of 1011 °C is 2.7% . Therefore, when the alloy contains a certain amount of CO, the strength of bronze plating can be improved by solid solution and aging treatment. A small amount of CO (0.2% ~ 0.5%) can prevent the grain growth of beryllium bronze during heating, delay the decomposition of solid solution, inhibit the grain boundary reaction, and avoid the structure inhomogeneity near the grain boundary due to overaging, thus, the precipitation hardening effect of the alloy is improved.

 (2) titanium and beryllium can form a solid-soluble metal compound Tibe2. The maximum solid solubility of Tibe2 is 3.7% at 825 °C. when the eutectic temperature decreases, the solid solubility of Tibe2 decreases sharply, so Tibe2 has precipitation hardening effect. Titanium-rich compounds sometimes appear in Cu-Be-Ni alloys containing a small amount of TI. If the compounds are distributed in strips, the alloy will crack in layers during processing. The addition of 0.10% ~ 0.25% ti to Cu-Be alloy with a small amount of Ni can reduce the amount of hard and brittle phase 1 to the minimum and make the alloy structure uniform. On the one hand, the machinability and fatigue strength of the alloy can be improved, on the other hand, the material after aging has good elastic stability and low elastic lag; a small amount of titanium can refine the grain of both ingot and annealing material, reduce the diffusion speed of beryllium and weaken the grain boundary reaction, the results show that the precipitation phase in the grain boundary is prior to the dissolution phase, and the distribution of the precipitation phase is uniform.

(3) magnesium and magnesium decrease the solubility of beryllium in solid copper. The low melting point EUTECTIC CU 2mg + Cu can be found in the grain boundary of the alloy when 0.2% ー0.5% MG is added to the bronze plating containing 2% be. The melting point of the EUTECTIC CU 2mg + Cu is about 730 °C, which makes the material easy to crack during hot working. The addition of 0.02% ー0.15% MG to QBE1.9 and QBE2 alloys can not only refine the grain size, but also make the particle size of phase 1 smaller and evenly distributed, and improve the mechanical properties and stability of the materials. A small amount of magnesium has no effect on the solderability and corrosion resistance of beryllium bronze.

 (4) Fe content of Fe in Fe-like beryllium bronze should be less than 0.1% . If the iron content is too high, not only the iron-containing phase will Be formed, the microstructure of the alloy will Be uneven, and the corrosion resistance will Be reduced, but also the supersaturation of Be in the solid solution will Be decreased, that is, the precipitation hardening effect of the alloy will Be decreased. Iron can refine grain size, and solid solution Fe can delay the decomposition of supersaturated solid solution and inhibit grain boundary reaction.

 (5) a small amount of tin can dissolve in Beryllium bronze solid solution, delay the decomposition of supersaturated solid solution, significantly inhibit discontinuous precipitation at grain boundaries, and prevent over-aging. Therefore, tin can be used instead of part of beryllium, for example, the mechanical properties of copper alloys containing 1.30% be, 0.25% co, 3% sn and 1.0% zn are similar to that of QBe 2 bronze, and have high machinability.

 (6) manganese and beryllium can form MNBE2 which is soluble in solid melt. The maximum solubility of mn-be2 is 7.3% at 782 °C, and it will decrease obviously with the decrease of temperature, so the alloy has obvious precipitation hardening effect. Mn has no significant effect on the mechanical properties of beryllium bronze with high Be content, but has positive effect on the alloys with low Be content.

 (7) the addition of 0.9% ~ 1.1% AG to beryllium bronze containing 0.25% ~ 0.50% be and 1.1% ~ 1.7% co can not only improve the room temperature strength of the alloy after aging, but also keep the high electrical conductivity (50% ~ 55%) . This alloy is a good material for making welding electrodes. 

(8) Cosi, Co2si, Co3Si5 and COSI2 can be formed in SI alloy when Co and SI are contained in the alloy, which can improve the strength of the alloy. When the content of silicon is large enough, hard and brittle EUTECTIC can be formed with beryllium, which makes the toughness of the material greatly decreased. 

(9) a small amount of aluminum (0.4% ~ 0.8%) slightly increased the mechanical properties of cu-2% be alloy. (10) phosphorus promotes the grain growth of Cu-Be alloy during heating, accelerates the decomposition of solid solution, and forms fusible substance distributed in the grain boundary, which reduces the thermal hardness and improves the machinability of the alloy.

 (10) addition of 0.1% ~ 0.2% as to arsenic-beryllium bronze promoted grain boundary reaction and over-aging softening process. 

(11) the machinability of lead-beryllium bronze, such as C17300 alloy, is usually improved significantly by adding 0.2% ~ 0.3% pb. In addition, beryllium bronze containing 1.8% ~ 2.0% be and 0.20% ~ 0.25% PB is a good material for watch gears. PB accelerates grain boundary reaction of beryllium bronze and promotes softening.

4. Cu-Ni alloy is a continuous solid solution with infinite solution. When the temperature of Cu-Ni alloy is lower than 322 °C, there exists a rather wide composition-temperature range of metastable decomposition. The composition-temperature range and location of metastable decomposition can be changed by adding the third elements such as Fe, CR, Sn, Ti, Co, SI and Al to the Cu-Ni alloy. At the same time, some properties of the alloy can be improved. Cupronickel is not only a good structural material, but also an important high resistance and thermocouple alloy.

 (1) the solubility of zinc in Cu-ni solid solution is quite large, and zinc has a great effect on solid solution. When the NI content is constant, increasing the zn content will enhance the atmospheric corrosion resistance of the alloy. The common zinc cupronickel contains 5% ~ 18% NI and 43% ~ 72% cu, the rest is Zn, and its corrosion resistance, elasticity and strength are all high. 

(2) the solubility of Fe in Cu-Ni alloy is small, and it can dissolve 1.8% at 950 °C. At 300 °C it drops to 0.1% . Iron can improve the corrosion resistance and mechanical properties of Cu-Ni alloy, especially the seawater impact corrosion resistance of Cu-Ni alloy. Generally, the FE content of Cu-Ni-Fe alloy is not more than 2% , otherwise the alloy has the tendency of stress corrosion cracking, and if the FE content is more than 1% , the corrosion will intensify. 

(3) the solid solubility of AL in Cu-Ni alloy is low and decreases with the decrease of temperature. NI3AL compound can be produced in Cu-Ni-Al Alloy, which has obvious precipitation hardening effect and enhances the strength and hardness of the alloy. Aluminum significantly improves the strength and corrosion resistance of Cupronickel. But the cold formability of the material decreases. When the NI/AL RATIO IS 8 ~ 10, the alloy has the best comprehensive properties. 

(4) the content of manganese in white copper is not more than 14% . MNNI compound can Be formed in Cu-Ni-Mn Alloy, which has the effect of precipitation hardening. MN can improve the strength, corrosion resistance and elasticity of the alloy, and also can improve the resistance of Cu-Ni alloy to turbulence impact corrosion. However, the resistance to stress corrosion cracking of B19 alloy will decrease slightly, but the effect of MN is less than that of AL, SI, SN, CR, Be and so on. MN can eliminate the bad effect of excess carbon in Cu-Ni alloy and improve its processing properties. Cu-Ni-Zn alloy with a small amount of MN also has some beneficial effects. 

(5) tin, beryllium, titanium, silicon, carbon, chromium, zirconium, carbon, Boron and S, P, As, SB, Bi are impurity elements of Cupronickel, which should be controlled within the standard range. 

Source: Handbook of copper alloys and their processing

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