Transcript Chapter 6 - Nonferrous Metals and Alloys

Chapter 6
Nonferrous Metals and Alloys
Nonferrous Metals and Alloys
• Alloys containing no iron
• Usually more expensive than ferrous
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metals
Have wide range of applications.
Aluminum and Al Alloys
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Most abundant metallic element in the earth’s
crust (8%), second to iron in production.
Nonmagnetic, good corrosion resistance.
High thermal and electrical conductivity.
High strength to weight ratio.
Easy to form (containers and packaging,
aircraft and aerospace applications, marine
craft, electrical components, etc.).
Commercially pure aluminum (99.5 - 99.7%).
Magnesium and Mg Alloys
• Third most abundant metallic element in
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the earth s crust (2%).
Come from sea water - obtained
electrolytically or by thermal reduction.
Lightest engineering metal available.
Good vibration dampening
characteristics.
Magnesium Alloys (Cont.)
• High strength to weight ratio (alloyed with
other elements)
• Used for aircraft and missile components,
material handling equipment, lightweight
components.
• Oxidizes rapidly (pyrophoric) precautions
should be taken when machining, grinding,
etc.
Copper and Cu Alloys
• Best conductor of electricity and heat,
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good corrosion resistance
Non-magnetic
Used for electrical components, springs,
cooking utensils.
Brass and Bronze are the two most
common alloys of copper (zinc-Zn and
tin-Si).
Superalloys
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Strong, high corrosion and heat resistance,
resistant to fatigue and creep
Used in high temperature applications (jet
engines, turbines, nuclear industry).
Nickel (Ni)-based Alloys
• most common.
• magnetic (used for electromagnetic applications).
Others include Cobalt (Co)-based alloys, Iron
(Fe)-based alloys
Titanium and Ti Alloys
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Expensive
High strength to weight ratio, corrosion
resistant at high temperatures.
Surface contamination from hydrogen,
oxygen, or nitrogen can cause embrittlement, reducing toughness, and ductility.
Submarine hulls, marine components, jetengine components, orthopedic implants
Refractory Metals and Alloys
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High melting point, maintain strengths at
elevated temperatures (2000- 4000 °F).
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Molybdenum (Mo)
• most plentiful of refractory metals.
• Disadv. Low resistance to oxidation above 950 °F
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Niobium (Nb)
• also Columbium.
• Good oxidation resistance
Refractory Metals and Alloys
Tungsten (cont’d)
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Tungsten (W)
• Highest melting point of any metal– 6170 °F
• Poor resistance to oxidation
• Light bulb filaments, spark plugs, welders
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Tantalum (Ta)
• High melting point - 5425 °F
• Good ductility and resistance to corrosion
• Capacitors, furnaces, heat exchangers
Other Nonferrous Metals and
Alloys
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Beryllium
• High strength-to-weight ratio
• Low neutron absorption
• Toxic.
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Zirconium
• Good strength and ductility at elevated
temperatures
• Low neutron absorption.
Low-melting Alloys
• Lead (Pb)
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High density and ductility.
Soft, corrosion resistant.
Toxic.
Used for piping, cable sheathing, radiation
shielding.
Low-melting Alloys (Cont.)
• Zinc (Zn)
• Fourth most utilized metal.
• Galvanizing.
• Is an alloy base for casting.
• Tin (Sn)
• Soldering materials, containers, protective
coatings.
Precious Metals
• Costly, soft, and ductile, used for
electrical contacts and terminals, as well
as for jewelry, dental, and decorative
purposes.
• Gold, Silver, Platinum
Shape-memory Alloys
• After plastically deformed at room
temperature, can return to original
shape when heated.
• e.g. 55% Ni, 45% Ti.
• Thermostats, valves, electrical components
Amorphous Alloys
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No long-range crystalline structure (no grain
boundaries), atoms randomly packed.
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Also called Metallic Glasses.
Contain iron, nickel, and chromium (usually
alloyed with carbon, phosphorus, boron,
aluminum, and silicon).