copper alloys_bw.pdf

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1/10/2010 G. Ubertalli

Bibliography: Metals handbook Vol. 2 Xa Ed.

The copper has a red-orange colour.

Melting temperature is 1083 C.

Lattice structure is FCC. Lattice structure is FCC.

Density of 8,900 Kg/m3 (3xAl).

Elastic Modulus 130 GPa.

Low electric resistivity (17 n at 20C).

Good thermal conductivity.

High corrosion resistance, (it is before hydrogen


High corrosion resistance, (it is before hydrogenin electrochemical series).

High ductility and malleability (therefore highpossibility of conducting current in fine andflexible wire).

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Copper in pennies (USA)

1793-1837 US penny made from pure Cu

1837-1857 US penny bronze (Cu-Sn)

1857 penny 88% Cu + 12%Ni (whitish appearance) 1857 penny 88% Cu + 12%Ni (whitish appearance)

1864-1962* US penny bronze (95% Cu+5% Zn and

Sn)

1962-1982 - 95 percent Cu + 5% Zn

1982-present Cu-plated Zn (97.5%Zn + 2.5% Cu)

* In 1943, the coin's composition was changed to zinc-

coated steel - due to the critical use of copper for the war

effort.


Over time, the copper roofs of Canada's Parliament Buildings and the statue of

liberty become covered with a layer of copper acetate, which produces the green

colour and prevents further corrosion.


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Typical applications Cu alloys

Electricity conduction (power/data Electricity conduction (power/data

transmission)

Heat conduction (radiators)

Marine condensers, or exposed marine

fixtures (heat/salt water exposure)fixtures (heat/salt water exposure)

Coin blanks (pennies)


Effect of additions on conductivity

All decreaseAll decrease

conductivity

especially P

Then Si, Fe,

Ar, Be


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Deoxidizers Li, Na, Be, Mg, B, Al, C, Si and P can be used

Ca, Mg and Zn sometimes normally other roles

Requirements of a deoxidizer Requirements of a deoxidizer

1. affinity for oxygen in molten copper

2. relatively inexpensive compared to copper and any

other additions

EXAMPLE

Zn normally solid-solution strengthener, sometimes added Zn normally solid-solution strengthener, sometimes added

in small amounts as deoxidizer

In tin bronze, traditionally use P thus Phosphor bronzes

In chromium-coppers Si not P:

P severely reduces electrical conductivity


Relative electrical and thermal conductivites

of commercially pure metals (at 20C)


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Cu and Cu Alloys

Advantages

Good corrosion

Disadvantages

Susceptibility to hydrogen Good corrosion

resistance

Excellent electrical and

thermal conduction

Variance in colour with

alloy addition (aesthetic

value)

embrittlement, stress

corrosion cracking

Relatively low

strength/weight alloy (when compared to Al or steel)

Properties are subject to

dramatic changes withvalue)

Ease of fabrication due

to excellent ductility

(rolled stamped, drawn)


dramatic changes with

varying alloy content

(i.e. conductivity decreases

substantially with increasing

impurity content)

Copper and its alloys

Family Alloying element Solid solubility at%Family Alloying element Solid solubility at%

Brasses Zinc (Zn) 37

Phosphor bronze Tin (Sn) 9

Al bronze Aluminium (Al) 19

Si bronze Silicon (Si) 8

Cu-nickel,Nickel- Nickel (Ni) 100Cu-nickel,Nickel-

silver

Nickel (Ni) 100


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Copper and its alloys

Solid solution alloys (Zn, Sn, Al, Si) Solid solution alloys (Zn, Sn, Al, Si)

Age-hardenable alloys (Be, Zr, Cr)

Insoluble alloying elements (lead, tellurium,

selenium)

Deoxidizers (Li, Na, Mg, B, Al, C, Si and P) Deoxidizers (Li, Na, Mg, B, Al, C, Si and P)


Name UNS Number Composition

Wrougth Alloys Copper C10100-C15760 > 99% Cu

Copper C16200-C19600 > 96% Cu

Brass C20500-C28580 Cu-Zn

Lead Brass C31200-C38590 Cu-Zn-Pb

Lead Brass C40400-C49080 Cu-Zn-Sn-Pb

Phosphorus Bronze C50100-C52400 Cu-Sn-P

P-Pb Bronze C53200-C54800 Cu-Sn-Pb-P

Cu-P and Cu-Ag-P Alloys C55180-C55284 Cu-P-Ag Cu-P and Cu-Ag-P Alloys C55180-C55284 Cu-P-Ag

Aluminium Bronze C60600-C64400 Cu-Al-Ni-Fe-Si-Sn

Silicon Bronze C64700-C66100 Cu-Si-Sn

Other Cu-Zn alloys C66400-C69900 . . . .

Copper Nickel C70000-C79900 Cu-Ni-Fe

Copper Nickel - Silver C73200-C79900 Cu-Ni-Zn

Cast Alloys Copper C80100-C81100 > 99% Cu

Copper C81300-C82800 > 94% Cu

Red and Pb Brass C83300-C85800 Cu-Zn-Sn-Pb (75-89% Cu)

Yellow and Pb Brass C85200-C85800 Cu-Zn-Sn-Pb (57-74% Cu)


Yellow and Pb Brass C85200-C85800 Cu-Zn-Sn-Pb (57-74% Cu)

Mn and Mn-Si Brass C86100-C86800 Cu-Zn-Mn-Fe-Pb

Silicon Bronze and Brass C87300-C87900 Cu-Zn-Si

Sn and Sn-Pb Bronze C90200-C94500 Cu-Sn-Zn-Pb

Ni-Sn Bronze C94700-C94900 Cu-Ni-Sn-Zn-Pb

Aluminium Bronze C95200-C95810 Cu-Al-Fe-Ni

Copper Nickel C96200-C96800 Cu-Ni-Fe

Nickel-Silver C97300-C97800 Cu-Ni-Zn-Pb-Sn

Copper-Leas C98200-C98800 Cu-Pb

Different alloys C99300-C99750 . . . .

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The oxygen has a very

low solubility in Cu solid low solubility in Cu solid

solution; therefore even a

very low percentage

induces the precipitation

of oxide Cu2O, which

decrease the copper

electric conductivity.


electric conductivity.


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Brasses

%Cu %Zn Brass

95 5 Gilding metal95 5 Gilding metal

90 10 Commercial bronze

85 15 Red brass

80 20 Low brass

70 30 Cartridge brass70 30 Cartridge brass

65 35 Yellow brass

60 40 Muntz metal (+)


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Brasses

Alloys of Cu-Zn - cheaper than Cu

Solid solution to ~38% Zn (~32.5% Zn)

3 alloys: 3 alloys:

(cold working alloys),

+ ,

(hot working alloys)

Strength increases a lot in the + region

Ductility drops more brittle

7030 or 6535 brass:

high strength,

high ductility



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Cu-Al phase diagram

aluminum bronzes


Influence of Al on properties of bronzes

Increase ductility Increase ductility

(if adding < 8%)

what happens at 8%?

Increase strength


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Cu-Ni phase diagram


Influence of Ni on properties


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Alloy C26000

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Brass ribbon (1 mm depth)

200

300

400

500

200 300 400 500 600 700 800Tensile strength [MPa]

Annealing Temperature[C]

0,12Alloy C22600.

0

0,03

0,06

0,09

0,12

200 400 600 800

Grain Size [mm]

Annealing Temperature[C]

Ribbon (1 mm - 1 hour

annealed) for jewellery.

Initial grain size of 0,035 mm,

cold rolled - 50% of

reduction.

60


0

20

40

60

200 300 400 500 600 700 800

Elongation %

(50 m

m)

Annealing Temperature [C]

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Age hardenable

1.87% Be solutionised @

800C, quenched, aged 4h

@ 350C.@ 350C.

intermediate

CuBe phase



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copper alloys_bw.pdf