Transcript Slide 1

ENMAT101A Engineering Materials and Processes
Associate Degree of Applied Engineering
(Renewable Energy Technologies)
Lecture 16 – Copper and its alloys
www.highered.tafensw.edu.au
TAFE NSW -Technical and Further Education Commission
Copper and its alloys
Reference Text
Section
Higgins RA & Bolton, 2010. Materials for Engineers and Technicians,
5th ed, Butterworth Heinemann
Ch 16
Additional Readings
Section
EMMAT101A Engineering Materials and Processes
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Copper and its alloys
Note: This lecture closely follows text (Higgins Ch16)
EMMAT101A Engineering Materials and Processes
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Copper
(Higgins 16.1)
READ HIGGINS 16.1
Some history…
Bronze-age weaponry
And for a bit more up-to-date action…
http://en.wikipedia.org/wiki/File:Bronze_ag
e_weapons_Romania.jpg
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Uses of copper
http://www.inmetmining.com
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Worldwide Copper Production
Worldwide
Copper
Production may
be nearing its
peak.
Copper is closely
linked to demands of
industrial expansion–
needed for both
infrastructure and
electrical products.
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Copper Price
The price of copper is sensitive to production
demands (set by manufacturing outlook: i.e.
companies placing orders based on their projected
production)
It is also magnified
by tightening
supply as China
and India increase
demand.
So copper price
rises on optimism.
Note the GFC drop.
http://www.kitcometals.com
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The extraction copper
(Higgins 16.2)
READ HIGGINS 16.2
The extraction of copper
The 2010 Copiapó mining
accident in Chile’s San José
copper–gold mine. The 33
miners were trapped 700m
underground, surviving for a
record 69 days before their
rescue through drilled holes.
Extraction of copper
Wikipedia
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Properties of copper
(Higgins 16.3)
READ HIGGINS 16.3
Conductivity (electrical and thermal)
Corrosion resistance
Ductility
http://www.sciencelearn.org.nz
http://www.reuters.com
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Coppers and alloys
(Higgins 16.4)
READ HIGGINS 16.4
Oxygen-free high-conductivity
(OFHC) copper: Electrolytically
refined: Electrical uses
'Tough-pitch' copper: Heat
refined. Lower conductivity.
Deoxidised copper: Tough pitch
copper deoxidised with
phosphorus which improves
weldability, but worse electrically.
The Xstrata copper electrorefining tankhouse at
Copper Refineries in Townsville, Queensland,
Australia.
EMMAT101A Engineering Materials and Processes
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Coppers and alloys
(Higgins 16.4)
READ HIGGINS 16.4.1: Alloys of copper
1. Brasses: copper-zinc alloys
2. Bronzes: copper-tin alloys
Phosphor bronzes: copper-tin-phosphorus alloys
Gunmetals: copper-tin-zinc alloys
3. Aluminium bronzes: copper-aluminium alloys
4. Cupro-nickels: copper-nickel alloys
Nickel silvers: copper-zinc-nickel alloys
5. Beryllium bronzes: copper-beryllium alloys
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The brasses (Higgins 16.5)
Brass
READ HIGGINS 16.5: CAREFULLY!
Brass: Up to 45% Zn, also some Sn, Pb, Al, Mn, Fe
Figure 16.1 The section of the copper-zinc equilibrium diagram which covers
brasses of engineering importance. (Higgins)
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The brasses
(Higgins 16.5)
Complete copper-zinc
equilibrium diagram:
Phases:
a up to 37% Zn:
Ductile: e.g. 70/30
Cold working
b above to 37% Zn
Hot working
Tin: corrosion
Lead: machinablilty
http://pwatlas.mt.umist.ac.uk
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The brasses (Higgins 16.5)
READ HIGGINS 16.5: CAREFULLY!
70/30 Brass: That’s copper/zinc ratio
(i) 70-30 brass as cast
with cored crystals of a
solid solution
(ii) 70-30 brass, cold
worked and then
annealed at 600°C.
The coring of the
original cast structure
has been removed by
this treatment and
recrystallisation has
produced small crystals
(twinned) of the solid
solution a
(Higgins Fig 16.2)
EMMAT101A Engineering Materials and Processes
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The brasses (Higgins 16.5)
READ HIGGINS 16.5: CAREFULLY!
Brass: Up to 45% Zn, also some Sn, Pb, Al, Mn, Fe
(iii) 60-40 brass as
cast. This shows a
typical Widmanstdtten
structure and, on
cooling, small a
crystals (light) have
precipitated from the b
phase (dark).
(Higgins Fig 16.2)
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Higgins
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Higgins
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The brasses (Higgins 16.5)
READ HIGGINS 16.5.1 'Shape memory' alloys
'Shape memory' alloys have two distinct crystal structures that revert at a
critical transformation temperature. Below the CTT structure is like
martensite, and reverts back when heated above CTT.
The shape change can be used to operate temperature-sensitive devices:
automatic greenhouse ventilators, thermostatic radiator valves, de-icing
switches, electric kettle switches and valves in solar heating systems.
Note:
The most widely used shape memory alloy is the equi-atomic Nickel Titanium alloy
known commercially as Nitinol.
http://www.doitpoms.ac.uk/tlplib/superelasticity/uses.php
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Tin bronzes (Higgins 16.6)
READ HIGGINS 16.6
Tin bronzes, contain up
to 18% Sn (Tin) with
smaller amounts of P,
Zn, Pb
1. Wrought tin bronzes
up to 7% tin. Sheet,
wire, drawn rod.
2 Cast tin bronzes with
10 to 18 % tin, used
mainly for bearings.
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Bronzes (Higgins 16.6)
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Bronzes (Higgins 16.6)
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Aluminium bronzes (Higgins 16.7)
READ HIGGINS 16.7
Two groups: coldworking alloys, and the
hot-working alloys.
1. Wrought tin bronzes
up to 7% tin. Sheet,
wire, drawn rod.
2 Cast tin bronzes with
10 to 18 % tin, used
mainly for bearings.
33 tonne propellor made from nickel aluminum bronze.
qe-carrier.blogspot.com
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Aluminium bronzes (Higgins 16.7)
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Copper-nickel alloys (Higgins 16.8)
READ HIGGINS 16.8
Cu and Ni complete solubility. Corrosion resistant.
16.8.1 Nickel-silvers
EMMAT101A Engineering Materials and Processes
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Other copper alloys (Higgins 16.9)
READ HIGGINS 16.9
16.9.1 Beryllium bronze
Non-sparking tools
16.9.2 Copper-chromium
Conductive & strong.
16.9.3 Copper-cadmium
Drawn electrical wire
16.9.4 Copper-tellurium
Machined electrical
16.9.5 Arsenical copper
Thermal
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Online Resources.
Cast Iron
http://www.msm.cam.ac.uk/phase-trans/2001/adi/cast.iron.html
Extraction of copper
EMMAT101A Engineering Materials and Processes
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GLOSSARY
Brass
Bronze
Electrolysis
Phosphor bronzes
Gunmetals
Aluminium bronzes
Cupro-nickels
Nickel silvers
Beryllium bronzes
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QUESTIONS
Moodle XML: Some questions in 10105 Steel
1.
2.
3.
4.
5.
Define all the glossary terms.
Describe the name, uses and properties of 70/30 brass.
What constituents determine the names brass and bronze?
Describe how electrical grade copper is made.
Explain why applications that used copper alloys (e.g. cartridge brass) are being
replaced with aluminium and mild steel.
6. Using current prices from LME (London Metals Exchange), determine the cost of
ingredients for 1 tonne of High-tin bronze – Higgins Table 16.2.
7. Describe the following copper-based alloys and their uses. Monel, gunmetal,
gilding metal, cartridge brass, free-cutting brass
8. What ingredient is added to brasses and bronzes to improve machability. Describe
how this works in reference to microstructure.
9. Silver is the most conductive metal. By comparison, copper is 97%, gold 71% and
aluminium 58%. Using current prices of each metal, rank conductivity per dollar.
10. Research the advantages and disadvantages of using aluminium vs copper for
use as electrical conductors. Why is strength and conductivity difficult?
EMMAT101A Engineering Materials and Processes
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