Nonferrous Metals


Reading Assignment:

  • 7.1 Introduction to Nonferrous Metals and Alloys
  • 7.2 Copper and Copper Alloys
  • 7.4 Zinc-Based Alloys
  • 7.5 Magnesium
  • 7.6 Titanium
  • 7.7 Nickel
  • 7.8 Superalloys
  • 7.9Lead and Tin
  • 7.10 Some Lesser Known Metals and Alloys
  • 7.11 Metallic Glasses
  • 7.12 Graphite

Additional Reading


Usage of nonferrous metals and alloys has increased due to technology

Possess certain properties that ferrous materials do not have:

  • Resistance to corrosion
  • Ease of fabrication
  • High electrical and thermal conductivity
  • Light weight
  • Strength at elevated temperatures
  • Color
  • Changes in Automotive Material Usage

Copper and Copper Alloys

  • General properties and characteristics
    • Backbone of the electrical industry
    • Base metal of a number of alloys such as bronzes and brasses
  • High electrical and thermal conductivity
  • Useful strength with high ductility
  • Corrosion resistance
  • About one-third of copper is used in electrical applications
  • Other uses are plumbing, heating, and air conditioning

General Properties and Characteristics

  • Relatively low strength and high ductility
  • Can be extensively formed
  • Heavier than iron
  • Problems can occur when copper is used at higher temperatures
  • Poor abrasive wear characteristics

Characteristics of Copper

  • Low temperature properties are better than most other materials
    • Strength increases with decreasing temperature
    • Material does not embrittle
    • Retains ductility under cryogenic conditions
    • Conductivity increases with a drop in temperature
  • Nonmagnetic
  • Nonpyrophoric
  • Nonbiofouling
  • Wide spectrum of colors

Commercially Pure Copper

  • Electrolytic tough-pitch (ETP) copper is refined copper containing between 0.02 and 0.05% oxygen
  • Used as a base for copper alloys
  • Used for electrical applications such as wire and cable
  • Oxygen-free high conductivity (OFHC) copper provides superconductivity

Copper-Based Alloys

  • Copper is the base metal
    • Imparts ductility, corrosion resistance, and electrical and thermal conductivity
  • Standardized by the Copper Development Association (CDA)
  • Common alloying elements
    • Zinc
    • Tin
    • Nickel

Copper-Zinc Alloys

  • Zinc is the most common alloy addition
    • Known as brass
  • Alpha brasses
    • Ductile and formable
    • Strength and ductility increase with increasing zinc content
  • Two-phase brasses
    • High electrical and thermal conductivity
    • Useful engineering strength
    • Wide range of colors
  • Rubber can be vulcanized to it
  • Brasses have good corrosion resistance
    • Brasses with 20 to 36% zinc may experience dezincification when exposed to acidic or salt solutions
    • Brasses with more than 15% zinc may experience season-cracking or stress corrosion
  • Cold-worked brass is usually stress-relieved to remove residual stresses
  • Lead can be added to increase machinability

Copper-Tin Alloys

  • Tin is more cost effective than zinc
  • Alloys with tin are known as bronzes
    • Bronzes can technically be any copper alloy where the major alloy addition is not zinc or nickel
  • Bronzes have desirable mechanical properties
    • Good strength
    • Good toughness
    • Good wear resistance
    • Good corrosion resistance
  • Often used for bearings, gears and fittings with high compressive loads

Copper-Nickel Alloys

  • Copper and nickel exhibit complete solubility
  • High thermal conductivity
  • High temperature strength
  • Corrosion resistance to a range of materials
  • High resistance to stress-corrosion cracking
  • Ideal choice for heat exchangers

Aluminum and Aluminum Alloys

General Properties and Characteristics

  • Second to steel in quantity and usage
  • Used in transportation, packaging, containers, building construction, etc.
  • Workable, light weight, corrosion resistance, thermal and electrical conductivity, optical reflectivity, easily finished
  • Aluminum is about 1/3 the weight of steel for an equivalent volume
  • Four to five times more expensive than steel per pound
  • Easily recycled with no loss in quality
    • About a 50% recycling rate in the United States
  • Biggest weakness of steel is it low modulus of elasticity

Commercially Pure Aluminum

  • Soft, ductile, and low strength
  • In the annealed condition, pure aluminum has about 1/5th the strength of hot rolled steel

Aluminums for Mechanical Applications

  • On a strength to weight basis, aluminum alloys are superior to steel
  • Wear, creep, and fatigue resistance are lower
  • For the most part, not suitable for high temperature applications
  • Performs well in low temperature applications
    • Stronger at subzero temperatures than at room temperature

Aluminum vs. Steel

  • A selection between aluminum and steel depends on different variables
    • Cost
    • Weight
    • Corrosion resistance
    • Maintenance expense
    • Thermal or electrical conductivity
  • For the automotive industry, aluminum has become increasingly used because of its lower strength to weight ratio and therefore improves fuel efficiency
    • Use of aluminum in vehicles has doubled in cars and tripled in SUVs
  • Corrosion Resistance of Aluminum and its Alloys
    • Pure aluminum is reactive and is easily oxidized
    • Oxide provides corrosion resistance layer
  • Aluminum oxides are not as reactive as pure aluminum and therefore are not as corrosion resistant
  • Oxide coating may cause difficult when welding
  • Welding may be done in a vacuum or in inert gas atmospheres

Classification System

  • Wrought alloys are shaped as solids
    • First digit indicates the major alloy element
    • Second digit indicate a modification or improvement
    • Last two digits indicate the alloy family
    • Temper designations
      • F: fabricated
      • H: strain hardened
      • O: annealed
      • T: thermally treated
      • W: solution-heat-treated only

Wrought Alloys



Major Alloying Element
Aluminum, 99.00%
Magnesium and sulfate

Only moderate temperatures are required to lower strength, so wrought alloys may be easily extruded, forged, drawn, and formed with sheet metal operations

Aluminum Casting Alloys

  • Pure aluminum is rarely cast
  • High shrinkage and susceptibility to hot cracking

Classification system


Major Alloying Element
Aluminum, 99.00%
Silicon with Cu and/or Mg
Other elements


  • First digit indicates the alloy group
  • Second and third digit indicates the particular alloy
  • Last digit indicates the product form

Other Forms of Aluminum

  • Aluminum-Lithium Alloys
    • Lithium is the lightest of all metallic elements
      • Light weight without compromising strength and stiffness
      • Fracture toughness, ductility, and stress corrosion are lower
  • Aluminum Foams
    • Made by mixing ceramic particles with molten aluminum and blowing gas into the mixture
      • Resembles metallic Styrofoam
    • Fuel cells of race cars may use aluminum foams
    • Provide excellent thermal insulation, vibration damping, and sound absorption

Magnesium and Magnesium Alloys

General Properties and Characteristics

  • Lightest of commercially important materials
  • Poor wear, creep, and fatigue properties
  • Highest thermal expansion of all engineering metals
  • Strength drops with increase in temperature
  • Low modulus of elasticity requires thick parts
  • High strength to weight ratio
  • High energy absorptions and good damping
  • Used in applications where light weight components are the primary concern

Magnesium Alloys and Their Fabrication

  • Classification system is specified by ASTM
  • Two prefix letters designate the two largest alloying metals
  • Numbers following the two letters indicate the percentages of the two main alloy elements
  • Magnesium alloys are often processed with sand, permanent mold, die, semisolid, and investment casting
    • Wall thickness and draft angle are lower than for aluminum
  • Improved machinability

Zinc-Based Alloys

  • Over 50% of all metallic zinc is used for galvanizing
  • Steel or iron may be hot dipped or be coated using electrolytic plating
  • Provides excellent corrosion resistance
  • Also used as the base metal in many die casting alloys
    • Reasonably high strength and impact resistance
    • Can be cast close to dimensional tolerances with extremely thin section
    • Low energy costs due to low melting temperature


Titanium and Titanium Alloys

  • Titanium is a strong, lightweight, corrosion resistant metal
  • Properties are between those of steel and aluminum
  • Less dense than steel
  • Can be used in high temperature applications
  • High energy costs for fabrication
  • Fabrication methods: casting, forging, rolling, extrusion, welding
  • Abundant material, but is difficult to process from ore
  • Aerospace applications, medical implants, bicycles, heat exchangers are common uses

Nickel Based Alloys

  • Outstanding strength and corrosion resistance at high temperatures
    • Wrought alloys are known as Monel, Hastelloy, Inconel, Incoloy, and others
    • Good formability, creep resistance, strength and ductility at low temperatures
  • Can be used in food-processing industries, turbine blades
  • Electrical resistors and heating elements typically use nickel-chromium alloys (Nichrome)
  • Superalloys are those alloys that are suitable for high temperature applications

Superalloys and Refractory Metals

  • Alloys based on nickel, iron, cobalt
  • Retain most of their strength even after long exposures to high temperatures
  • Strength comes from solid solution strengthening, precipitation hardening, and dispersion strengthening
  • The density of superalloys is much greater than that of iron
  • Difficult to machine
    • Electrodischarge, electrochemical, ultrasonic machining, powder metallurgy

High Temperature Alloys

  • Refractory metals
    • Use niobium, molybdenum, tantalum, rhenium, and tungsten
    • Coating technology is difficult because of their ceramic coating
  • Intermetallic Compounds
    • Provide properties between metals and ceramics
    • Hard, stiff, creep resistant, oxidation resistant, high-temperature strength
    • Poor ductility, poor fracture toughness, and poor fatigue resistance
    • Difficult to fabricate

Lead, Tin, and Their Alloys

Lead alloys

  • High density, high strength and stiffness
  • Storage batteries, radiation absorption
  • Good corrosion resistance, low melting point, ease of casting or forming


Metallic Glasses

  • Amorphous metals are formed by cooling liquid metal extremely quickly so that no crystalline structure can form
    • Lacks grain boundaries and dislocations
    • High strength, large elastic strain, good toughness, wear resistance, magnetic, corrosion resistance
    • Used in load bearing structures, electronic casings, sporting goods


  • Properties of metals and nonmetals
  • Good thermal and electrical conductivity
  • Can withstand high temperatures
  • Lubricant
  • Used as electrodes in arc furnaces
  • Rocket-nozzles
  • Permanent molds for casting


  • Nonferrous metals are used in a variety of applications
  • Many nonferrous metals are lower in weight than steel and are used in applications where weight is a consideration
  • Many have better corrosion resistance than steels
  • Nonferrous metals are often more expensive than iron based metals or alloys

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