Chapter 07:

Nonferrous Metals and Alloys

DeGarmo’s Materials and Processing in

Manufacturing
7.1 Introduction

 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
Common Nonferrous Metals and Alloys

Figure 7-1 Some common nonferrous metals and alloys, classified by attractive engineering
property.
7.2 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
 Main properties
 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
 Whole spectrum of fabrication processes: casting,
machining, joining, surface finishing
 Heavier than iron
 Problems can occur when copper is used at higher
temperatures (tend to soften above 220 °C)
 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 (not burn in air, nonsparking)
 Nonbiofouling (inhibit organism growth)
 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
Designation Systems for Copper

Alloy numbered from 100 to 199 - copper with less than 2% alloy addition
Alloy numbered from 200 to 799 - wrought alloys
Alloy numbered from 800 to 900 series – cast alloys
Copper-Zinc Alloys (Brass)

 Zinc is the most common alloy addition

 Known as brass
 Alpha brasses (< 36%Zn)
 Ductile and formable
 Strength and ductility increase with increasing zinc content
 Cartridge brass (70%Cu-30%Zn) - popular material for sheet-forming
operation
 Rubber can be vulcanized to it without special treatment
 Two-phase brasses (>36%Zn)
 Two-phase region involving a brittle zinc-rich phase and ductility drops
markedly
 High electrical and thermal conductivity
 Useful engineering strength
 Wide range of colors
Copper-Zinc Alloys (Brass)

 Brasses have good corrosion resistance

 Naval brass is 40% zinc Muntz metal with Tin addition
 Tin addition improves resistance to seawater corrosion
 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 cracking
 Cold-worked brass is usually stress-relieved to remove
residual stresses to prevent stress corrosion
 2-3% Lead can be added to increase machinability
 50-55%Copper and remainder Zinc is used as a filler in
brazing
Copper-Tin Alloys (Tin Bronzes)
 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
 Tin bronzes contain less than 12% Tin
 Strength increase with the increasing Tin up to 20%, but high-tin alloys tend
to be brittle
 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
 10% Lead is frequently added to copper-tin alloys for bearing
application
Copper-Nickel Alloys

 Copper and nickel exhibit complete solubility

 Key features:
 High thermal conductivity
 High temperature strength
 Corrosion resistance to a range of materials
 High resistance to stress-corrosion cracking
 Ideal choice for heat exchangers, cookware, desalination
apparatus and variety of coinage
 Cupronickels contain 2 to 30% nickel
 Nickel silvers contain 10 to 30% nickel and 5% zinc
 Constantan contains 45% nickel
 Monel contains 67% nickel
Other Copper-Based Alloys

 Aluminum-bronze
 High strength and corrosion resistance
 With less than 8% Aluminum, the alloys are very ductile
 Marine hardware, power shafts, pump and valve components
 Silicon-bronze
 Contain up to 4% silicon and 1.5% zinc
 Strength, formability, machinability, and corrosion resistance
 Boiler tanks, stove applications
 Copper-beryllium
 Contain up to 2.5% Beryllium
 Highest strengths, nonsparking, nonmagnetic, electrically and
thermally conductive
 Electrical contact springs
Lead Additions and Lead-Free Casting
Alloys
 Addition of lead can serve as a lubricant and
chip breaker in machining processes
 Used in many plumbing components
 Due to increased concerns with lead in drinking
water, bismuth and selenium are often
substituted for lead
 EnviroBrass alloys
 Somewhat lower in ductility, but have other properties
similar to lead alloys
7.3 Aluminum and Aluminum Alloys

 General Properties and Characteristics

 Second to steel in quantity and usage
 Used in transportation, packaging, containers, building
construction, etc.
 Workability, 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
Characteristics of Aluminum

 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 aluminum is its low modulus of
elasticity
 About 1/3 that of steel
 Commercially Pure Aluminum
 Soft, ductile, and low strength
 In the annealed condition, pure aluminum has about 1/5th the
strength of hot rolled steel
 Electrical-conductor-grade aluminum is used in large quantities
and has replaced copper in many application due to the heavy
weight of copper
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 (above 150°C)
 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
Weight Savings Designs

Figure 7-3 The all- aluminum space frame of the

2012 Audi S8 sedan.
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

 Aluminum alloy can be divided into two groups

based on the method of fabrication:
 Wrought aluminum alloys
 Low yield strength
 High ductility
 Good fracture resistance
 Good strain hardening
 Casting aluminum alloys
 Low melting point
 High fluidity
 Resistance to hot cracking during and after solidification
Wrought Aluminum Alloys

 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
 Example, 2024 – alloy number 24 within the 2xxx, or
aluminum-copper system
Wrought Aluminum Alloys
Major Alloying Element
Aluminum, 99.00% 1xxx
Copper 2xxx
Manganese 3xxx
Silicon 4xxx
Magnesium 5xxx
Magnesium and sulfate 6xxx
Zinc 7xxx
Other 8xxx

 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
 First digit indicates the alloy group
 Second and third digit indicates the particular alloy
 Last digit, separated by a decimal point, indicates the product form
Major Alloying Element
Aluminum, 99.00% 1xx.x
Copper 2xx.x
Silicon with Cu and/or Mg 3xx.x
Silicon 4xx.x
Magnesium 5xx.x
Zinc 7xx.x
Tin 8xx.x
Other elements 9xx.x

Note wrought aluminum alloys 1xxx

aluminum casting alloys 1xx.x
Other Forms of Aluminum
 Aluminum-Lithium Alloys
 Lithium is the lightest of all metallic elements
 Each percent of lithium reduces the overall weight by 3% and
increases stiffness by 6%
 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
7.4 Magnesium and Magnesium Alloys
 General Properties and Characteristics
 Lightest of commercially important materials
 Magnesium weight is 2/3 of Aluminum, 1/4 of steel
 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
 Modulus of elasticity is less than that of aluminum, 1/5 or 1/6 of that of
steel
 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

 Magnesium alloys are classified as either cast or wrought

 Classification system is specified by ASTM
 Two prefix letters designate the two largest alloying metals
A aluminum F iron M manganese R chromium
B bismuth H thorium N nickel S silicon
C copper K zirconium P lead T tin
D cadmium L beryllium Q silver Z zinc
E rare earth
 Numbers following the two letters indicate the percentages of
the two main alloy elements
 For example : AZ91 alloy would contain approximately 9%
aluminum and 1% zinc
Magnesium Alloys and Their Fabrication

 Magnesium alloys are often processed with sand,

permanent mold, die, semisolid, and investment casting
 Wall thickness, draft angle and dimensional tolerances are lower
than for aluminum
 Improved machinability
 Magnesium alloys are highly combustible when in a
finely divided form such as powder or fine chip
 No fire hazard in form of sheet, bar, extruded product or
finished casting
7.5 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
ZA-8 zinc aluminum casting alloys with 8% aluminum
ZA-12 zinc aluminum casting alloys with 12% aluminum
7.6 Titanium and Titanium Alloys
 Titanium is a strong, lightweight, corrosion resistant
metal
 Properties are between those of steel and aluminum
 Less dense than steel (density is 60% that of steel)
 Modulus of elastic is about 1/2 that of steels
 Can be used in high temperature applications
 Disadvantages: high cost, fabrication difficulties, 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
7.7 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 due to its corrosion resistance characteristics
 Electrical resistors and heating elements typically use
nickel-chromium alloys (Nichrome)
 Invar – an alloy of nickel and 36% iron has a near-zero
thermal expansion
 Superalloys are those alloys that are suitable for high
temperature applications
7.8 Superalloys and Other Metals
Designed for High-Temperature Service

 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
Figure 7-6 Temperature tungsten
scale indicating the upper
limit to useful mechanical
 Coating technology is difficult
properties for various
because of their ceramic
engineering metals.
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
Figure 7-7 Densities of the various engineering metals. The elevated-
temperature superalloys and refractory metals are all heavier than steel
7.9 Lead, Tin, and Their Alloys

 Lead and lead alloys

 High density, high strength and stiffness
 Storage batteries, cable cladding, radiation absorbing or sound-
and vibration-dampening shields
 Good corrosion resistance, low melting point, ease of casting or
forming
 Pure metal Tin is used as a corrosion resistant coating
on steel
 Tin alloys
 Used with lead
 Bearing materials: tin babbitt and lead babbitt
 Solder
7.10 Some Lesser Known Metals and
Alloys
 Beryllium
 Less dense than aluminum, greater stiffness than steel,
transparent to x-rays
 Used in nuclear reactors because of it low neutron absorption (as
well as hafnium and thorium)
 Uranium
 High density

 Cobalt
 Base metal for superalloys

 Zirconium
 Outstanding corrosion resistance

 High strength, good weldability, fatigue resistance

 Rare-earth metals is for magnetic properties

 Precious metals offer outstanding corrosion resistance and
electrical conductivity
7.11 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
7.12 Graphite

 Graphite
 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
 Carbon nanotubes and Graphene
 Graphene – mono-atomic layer carbon sheets with atoms in a
hexagonal arrangement
7.13 Materials for Specific Application
 Materials for outer space applications
 Must withstand ionizing radiation, wide extremes of temperature and
possible impacts from micrometeorites; lightweight
 Smart materials
 Can be used to control automated processes and equipment
 sensors and actuators
 Strong permanent magnets
 Aluminum-nickel-cobalt (AlNiCo), Samarium cobalt, neo-dymium iron
boron
 For hybrid vehicles and computer-activated motors in automobiles
 Medical Applications
 Joint replacements, medical implants, and medical devices
 Titanium, Tantalum, Niobium, Nitinol (memory alloy), cobalt-based
alloys
7.14 High Entropy Alloys

 High entropy alloys – a new class of multicomponent

alloys composed of five or more constituent elements,
each with a concentration between 5 and 35 atomic
percent.
 Lighter than conventional alloys
 High fracture resistance, tensile strength, hardness,
corrosion resistance, and oxidation resistance
 Structural stability and strength retention at extreme
elevated temperatures
 Ideal properties to replace superalloys
Summary

 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
Homework

 Review Questions (12th ed.) Chapter 7: 4, 5,

7

 Review Questions (11th ed.) Chapter 8: 4, 5,

7