GAZİ UNIVERSITY
Engineering Faculty
MATERIALS SCIENCE
2022-2023
Fall Semester
1
Text Book (1) and References (2-5):
1) Materials Science and Engineering, W.D. Callister, 8th ed., John Wiley,
2011.
2) The Science and Engineering of Materials, D.R. Askeland, P.P. Phule, 4th ed.,
Thomson Brooks/Cole, 2003.
3) Foundations of Materials Science and Engineering, W.F. Smith, J. Hashemi, 4th
ed. McGraw-Hill, 2006.
4) Engineering Metallurgy and Materials, Süleyman Sarıtaş, Gazi University, 1995.
5) Materials Science and Engineering, W.D. Callister, Translation to Turkish
from 8th ed., John Wiley, 2011.
2
3
Course Outline
Subject
1. Introduction to Engineering Materials………………………
Weeks
1
Classissification, Metals, Ceramics, Polymers, Composites
2. Interatomic Bonding………………………………………………
1
3. The Structure of Crystalline Solids ….………...……………
2
Atomic arrangements and crystals, Imperfections in crystals
Microstructural examination of materials
4. Diffusion………………………..…………………………….……..
1
5. Phase Diagrams…………...………………………………………
1
Rules of phase diagrams, Construction of phase diagrams
4
Course Outline, cont.
Subject
6. Mechanical Testing and Properties………………………
Weeks
2
Tensile test, Hardness test, Fatigue test, Creep test
Impact test, Bending and Shear (Torsion) tests
7. Ferrous and Nonferrous Alloys……………………………
2
8. Iron-Carbon System and Heat Treatments….…………
2
Atomic arrangements and crystals, Imperfections in crystals
Microstructural examination of materials
9. Strengthening Mechanisms………………………….……..
1
Work hardening, Solid solution hardening, ,
Grain size strengthening, Dispersion hardening
5
CHAPTER 1
INTRODUCTION TO ENGINEERING MATERIALS
(Text Book Pages 1-17)
.
7
“Because without materials, there is no engineering.”
Materials are probably more deep-seated in our culture than most of us
realize. Transportation, housing, clothing, communication and food
production-virtually every segment of our everyday lives is influenced by
materials. Then, what are materials?
Materials may be defined as substance of which something is
composed or made.
Materials are everywhere. Some of commonly encountered
materials are wood, concrete, brick, steel, plastic, glass,
rubber, aluminum, copper and paper.
8
Materials Science and Engineering?
Materials Science?
 Involves Investigating the relationships between structure,
processing and properties of materials.
Materials Engineering?
 On the basis of these structure-property correlations, designing or
engineering the structure of a material to produce a predetermined set
of properties. Designing the structure to achieve specific properties
of materials.
Structure means a description of the arrangements of atoms or ions in a material.
The structure of materials has a profound influence on many properties of materials,
even if the overall composition does not change!
9
Hot rolling
roll
round and coarse grains
low strength
high ductility
Relation between
processing & properties
elongated grains
high strength
low ductility
Recrystallised fine
grains
low strength
high ductility
10
11
What is the difference?
12
Why the study of materials is important?
Engineers choose materials to suit design or new materials might be needed for some new
applications. For example:
 Mechanical engineers search for high temperature resistant materials so that jet engines
can operate more efficiently.
Figure. A section through a jet engine. The forward compression section operates
at low to medium temperatures, and titanium parts are often used. The rear
combustion section operates at high temperatures and nickel-based superalloys
are required. The outside shell experiences low temperatures, and aluminum and
composites are satisfactory.
 Aerospace engineers search for materials with higher strength to weight ratios for aircraft
and space vehicles.
 Chemical engineers need more highly corrosion resistant materials.
So, engineers in all disciplines should have some basic and applied knowledge of
engineering materials.
Corrosion is the disintegration of an engineering material into its constituent atoms due to chemical reactions with
its surroundings. Formation of an oxide of iron due to oxidation of the iron atoms in solid solution is a well-known
example of corrosion (rusting).
13
CLASSIFICATION OF MATERIALS
Engineering materials are divided into three main classes: metals, ceramics,
and polymers.
In addition, there are
the composites,
combinations of two or
more of these basic
material classes.
14
METALS
Metals are metallic elements such as iron, aluminum, copper, titanium, nickel and
gold. Although pure metals are occasionally (rarely) used, alloys which
combinations of two or more metals are normally designed to provide desirable
properties. Examples:
Pure metals: Fe, Au, Ag, Cu, Ni, etc.
Alloys: Brass: Cu-Zn, Bronze: Cu-Sn,
Steel: Fe-C, Solder: Pb-Sn, etc.
Properties of metals
a) Atoms arranged in a regular repeating structure (crystalline structure)
b) Good strength: strong
c) Dense
d) Malleable or ductile (i.e., capable of large amounts of deformation without fracture):
high plasticity
e) Resistant to fracture and shock resistance: tough
f) Good thermal and electrical conductivity
g) Easy machinability: Thus, metals can be formed
h) They are least resistant to corrosion , such as iron-oxide (rust)
i) Some of the metals (Fe, Ni, Co) have desirable magnetic properties.
Applications:
 Buildings
 Automobiles
 Airplanes
 Machine and tools
 Gears
 Electrical wires
 Pressure vessels, etc.
Metals and alloys are generally divided into two groups: Ferrous (steel, cast iron)
and nonferrous (Al, Cu, Zn, etc.).
Ferrous metals and alloys that contain a large percentage of iron such as the
steel and cast irons. Nonferrous metals do not contain iron.
15
Ceramics
 Ceramic materials consist of metallic and
non-metallic elements chemically bonded
together.They are most frequently oxides,
nitrides, and carbides.
For example: SiC, Al2O3, ZrO2, Si3N4,.MgO
Examples:
 Abrasive Materials (for cutting, grinding
and polished other materials of lower
hardness; aluminium oxide and silicon
carbide)
 Refractories (corrosion and high heatresistant; brick)
 Whitewares (e.g. porcelains)
 Electrical
Ceramics
(capacitors,
insulators, transducers, etc.)
 Chemically Bonded Ceramics (e.g.
cement and concrete)
 Glass (transparency,hardness at room
temperature, excellent resistance to most
environments)
16
Properties of ceramics
 Except for glasses they have crystalline structure
 They have lower density than most metals
 Generally they have high melting points
 They have high chemical stabilities (resistant to environment)
 They have high wear resistance
 They have high hardness and high-temperature strength (heat resistant)
but they are very brittle
 They have low ductility or malleability: low plasticity
 They have very high elastic modulus
Ceramics are usually poor electrical and thermal conductors
17
 Aluminium (Al) is a common metal, but aluminium oxide, a
compound of aluminium and oxygen such as Al2O3, is ceramic.
Aluminium oxide has two basic advantages over metallic
aluminium.
 First, Al2O3 is chemically stable in a wide variety of severe
environments whereas metallic aluminium would be oxidized.
 Second, the ceramic Al2O3 has a significantly higher melting
point (2020 C) than does the metallic Al (660 C).
 This makes Al2O3 a popular refractory, that is, a hightemperature-resistant material of wide use in industrial furnace
construction.
 With its superior chemical and temperature-resistant
properties,
why
isn’t
Al2O3
used
for
certain
applications,such as automotive engines, in place of metallic
aluminium?
Applications
 Electrical
insulators
 Abrasives
 Thermal insulation
and coatings
 Windows,
television screens
(glass)
 Corrosion resistant
applications
 Electrical devices
 Highways and
roads (concrete)
 The answer to this question lies in the most limiting property of
ceramics-brittleness. Aluminium and other metals have the
desirable property of ductility whereas aluminium oxide and
other ceramics do not. Thus ceramics are eliminated from
many structural applications.
18
Polymers
 Polymers are in our everyday life. An alternative name for this category is
plastics. The “mer” in a polymer is a single hydrocarbon molecule. Polymers
are long-chain molecules composed of many mers bonded together.
 Many important polymers are simply compounds of hydrogen and carbon.
 Others contain oxygen, nitrogen,and silicon.
 Examples: nylon,teflon, PVC (polyvinyl chloride), polyester.

Plastics can be divided into two classes, thermoplastics and
thermosetting plastics, depending on how they are structurally bonded.
19
THERMOPLASTICS & THERMOSETTINGS
 Most thermoplastics consist
of very long molecular chains and
have good ductility and formability.
 These materials can be reheated
and reformed into new shapes a
number of times.
 Polyester (PE), polystyrene
(PS) and PVC are thermoplastics.
 Thermosetting
plastics
are
stronger but more brittle because the
molecular chains are tightly linked.
 Thermosetting plastics can not be
remelted and reformed into another
shape. Thus,
they cannot be
recycled.
 Epoxies, phenolics and some
polyster resins are thermosets.
20
Properties of polymers
Applications
 Most polymers are non-crystalline, but some
consist of mixtures of both crystalline and noncrystalline regions
 They generally have low densities
 They have low elastic modulus
 Their ductility may vary considerably
 They have low strength
 Most of them are corrosion resistant
 They cannot be used at high temperature
because of their low melting points
 They have low cost
 Adhesives and glues
 Containers
 Moldable products (computer
casing, telephone handset)
 Clothing and upholstery material
(polyester, nylon)
 Biodegradable products (packing)
 Low friction materials (teflon)
 Gaskets and O-rings (rubber)
 Most are poor conductors of electricity and heat
 In spite of the limitations, (they have low electrical and thermal conductivities, low
strength, and are not suitable for use at high temperature) polymers are highly versatile
(can be used for many different purposes) and useful materials.
 Unlike brittle ceramics, polymers which are frequently lightweight, low-cost and resistant
to higher chemical reactivity alternatives to metals in structural design applications.
21
Composite Materials
 Composites are produced when two materials are joined to give a combination
of properties that cannot be obtained in the original materials.
With composites we can produce
 lightweight
 strong
 ductile
 high temperature-resistant materials that are otherwise unobtainable.
 Composites can be
 metal-metal
 metal-ceramic
 metal-polymer
 ceramic-polymer
 ceramic-ceramic
 polymer-polymer
 Furthermore, some naturally-occurring materials are also considered to be
composites-for example, wood and bone.
22
 Fiberglass, in which small glass fibers are embedded within a polymeric material
(epoxy, polyster) is a common ceramic-polymer composite (GFRP: Glass Fiber
Reinforced Polymer). The glass fibers are relatively strong (but also brittle), whereas
the polymer is ductile (but also weak). Thus, the resulting composite material is
relatively strong and ductile. In addition, it has a low density.
 Another of these technologically important materials is the carbon fiber reinforced
polymer composite (CFRP: Carbon Fiber Reinforced Polymer). These composites
are stronger than glass fiber-reinforced composites, but they are more expensive.
They are used in some aircraft and aerospace applications, as well as high-tech
sporting equipment (e.g., bicyles, tennis rackets, and skis).
 Metal matrix-ceramic composites, for example, include silicon carbide or aluminium
oxide fiber reinforced aluminium alloy.
 WC reinforced cobalt matrix composite materials are also metal-ceramic composites.
It is used as a cutting tool for machining.
 Composites can be placed into three categories: particulate, fiber, and laminar-based
on the shapes of the material.
Applications
 Aircraft and aerospace applications
 Sports equipment (golf club shafts, tennis rackets, bicycle frames)
 Thermal insulation
 Concrete
 Brake materials
23
Fig.1.3. Bar chart of room temperature density values for various
materials
24
Fig.1.4. Bar chart of room temperature stiffness (i.e. Elastic
modulus) values for various materials
25
Fig.1.5. Bar chart of room temperature strength (i.e. Tensile
strength) values for various materials
26
Fig.1.6. Bar chart of room temperature resistance to fracture for
various materials
27
Fig.1.7. Bar chart of room temperature electrical conductivity
ranges for various materials
28
Advanced Materials
• Materials that are utilized in high-technology (or hightech) applications are sometimes termed advanced
materials.
• By high technology we mean a device or product that
operates or functions using relatively intricate and
sophisticated principles; examples include electronic
equipment (camcorders, CD/DVD players, etc.),
computers, fiber-optic systems, spacecraft, aircraft, and
military rocketry.
• These advanced materials are typically traditional
materials whose properties have been enhanced, and,
also newly developed, high-performance materials.
29
Advanced Materials, Cont.
Semiconductors
• Semiconductors have electrical properties that are intermediate
between the electrical conductors (viz. metals and metal alloys) and
insulators (viz. ceramics and polymers)—Figure 1.7.
• Furthermore, the electrical characteristics of these materials are
extremely sensitive to the presence of minute concentrations of
impurity atoms, for which the concentrations may be controlled over
very small spatial regions.
• Semiconductors have made possible the advent of integrated
circuitry that has totally revolutionized the electronics and computer
industries (not to mention our lives) over the past three decades.
30
Advanced Materials, Cont.
Biomaterials
• Biomaterials are
employed in
components
implanted into the
human body for
replacement of
diseased or
damaged body
parts.
31
Advanced Materials, Cont.
Biomaterials, cont
• These materials must not
produce toxic substances
and must be compatible
with body tissues (i.e.,
must not cause adverse
biological reactions).
• All of the above
materials—metals,
ceramics, polymers,
composites, and
semiconductors—may be
used as biomaterials.
32
Advanced Materials, Cont.
Smart Materials
• Smart (or intelligent) materials are a group of new and
state-of-the-art materials now being developed that will
have a significant influence on many of our technologies.
• The adjective “smart” implies that these materials are
able to sense changes in their environments and then
respond to these changes in predetermined manners—
traits that are also found in living organisms.
• In addition, this “smart” concept is being extended to
rather sophisticated systems that consist of both smart
and traditional materials.
33
Advanced Materials, Cont.
Smart Materials, cont.
•
•
•
Components of a smart material (or
system) include some type of sensor (that
detects an input signal), and an actuator
(that performs a responsive and adaptive
function).
Actuators may be called upon to change
shape, position, natural frequency, or
mechanical characteristics in response to
changes in temperature, electric fields,
and/or magnetic fields.
Four types of materials are commonly
used for actuators: shape memory
alloys, piezoelectric ceramics,
magnetostrictive materials, and
electrorheological/magnetorheological
fluids.
34
Advanced Materials, Cont.
Nanomaterials
• One new material class that has fascinating
properties and tremendous technological promise is
the nanomaterials.
• Nanomaterials may be any one of the three basic
types: metals, ceramics, or polymers.
• The ability to carefully arrange atoms provides
opportunities to develop mechanical, electrical,
magnetic, and other properties that are not otherwise
possible.
• We call this the “bottom-up” approach, and the study
of the properties of these materials is termed
“nanotechnology”;
• The “nano” prefix denotes that the dimensions of
these structural entities are on the order of a
nanometer (10-9 m)
35
Modern materials’ Needs
• In spite of the tremendous progress that has been made in the
discipline of materials science and engineering within the past few
years, there still remain technological challenges, including the
development of even more sophisticated and specialized materials,
as well as consideration of the environmental impact of materials
production. Some comment is appropriate relative to these issues so
as to round out this perspective:
–
–
–
–
Nuclear energy
Engine components (higher temperature capabilities)
Hydrogen fuel cell
Pollution control techniques
36
END of the CHAPTER 1
Don’t forget to study from the
TEXT BOOK!
pages 1-17
37