Chapter 6

Nonferrous Metals and Alloys

Nonferrous Metals and Alloys

• Alloys containing no iron

• Usually more expensive than ferrous metals

• Have wide range of applications.

• 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%).

Aluminum and Al Alloys

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.

• 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.

Magnesium Alloys (Cont.)

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).

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

• 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

Titanium and Ti Alloys

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

Refractory Metals and Alloys Tungsten (cont’d)

• 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

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.

Low-melting Alloys

• Lead (Pb)• 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.

• Costly, soft, and ductile, used for

electrical contacts and terminals, as well

as for jewelry, dental, and decorative

purposes.

• Gold, Silver, Platinum

Precious Metals

• After plastically deformed at room

temperature, can return to original

shape when heated.• e.g. 55% Ni, 45% Ti.

• Thermostats, valves, electrical components

Shape-memory Alloys

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).