Nonferrous Metals and Alloys

1
Chapter 6

• Nonferrous Metals and Alloys

2
Nonferrous Metals and Alloys

• Alloys containing no iron
• Usually more expensive than ferrous metals
• Have wide range of applications.

3
Aluminum and Al Alloys

• Most abundant metallic element in the earths
  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).

4
Magnesium and Mg Alloys

• Third most abundant metallic element in the earth
  s crust (2).
• Come from sea water - obtained electrolytically
  or by thermal reduction.
• Lightest engineering metal available.
• Good vibration dampening characteristics.

5
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.

6
Copper and Cu Alloys

• Best conductor of electricity and heat, 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).

7
Superalloys

• 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

8
Titanium and Ti Alloys

• Expensive
• High strength to weight ratio, corrosion
  resistant at high temperatures.
• Surface contamination from hydrogen, oxygen, or
  nitrogen can cause em-brittlement, reducing
  toughness, and ductility.
• Submarine hulls, marine components, jet-engine
  components, orthopedic implants

9
Refractory Metals and Alloys

• High melting point, maintain strengths at
  elevated temperatures (2000- 4000 F).
• Molybdenum (Mo)
• most plentiful of refractory metals.
• Disadv. Low resistance to oxidation above 950 F
• Niobium (Nb)
• also Columbium.
• Good oxidation resistance

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Refractory Metals and Alloys Tungsten (contd)

• Tungsten (W)
• Highest melting point of any metal 6170 F
• Poor resistance to oxidation
• Light bulb filaments, spark plugs, welders
• Tantalum (Ta)
• High melting point - 5425 F
• Good ductility and resistance to corrosion
• Capacitors, furnaces, heat exchangers

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Other Nonferrous Metals and Alloys

• Beryllium
• High strength-to-weight ratio
• Low neutron absorption
• Toxic.
• Zirconium
• Good strength and ductility at elevated
  temperatures
• Low neutron absorption.

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Low-melting Alloys

• Lead (Pb)
• High density and ductility.
• Soft, corrosion resistant.
• Toxic.
• Used for piping, cable sheathing, radiation
  shielding.

13
Low-melting Alloys (Cont.)

• Zinc (Zn)
• Fourth most utilized metal.
• Galvanizing.
• Is an alloy base for casting.
• Tin (Sn)
• Soldering materials, containers, protective
  coatings.

14
Precious Metals

• Costly, soft, and ductile, used for electrical
  contacts and terminals, as well as for jewelry,
  dental, and decorative purposes.
• Gold, Silver, Platinum

15
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

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Amorphous Alloys

• No long-range crystalline structure (no grain
  boundaries), atoms randomly packed.
• Also called Metallic Glasses.
• Contain iron, nickel, and chromium (usually
  alloyed with carbon, phosphorus, boron, aluminum,
  and silicon).