Course Book

Engineering Materials &

Minerals

Lecturer: Dr.Payman Suhbat Ahmed

E-mail: payman.suhbat@koyauniversity.org

Coordinator: Nawzat Rashad Ismail

E-mail: nawzat.rashad@koyauniversity.org

2nd

Stage

Petroleum Engineering Department

Engineering Faculty

Koya University

Course Overview In this course the student will learn in detail the very important topics in

Engineering Materials from the basics concepts to the traditional and advanced

application passing by their processing, characterization and testing to make

students able to select the appropriate material for the right application.

Course Objective To make students able to select the appropriate material for the right

application.

Course Reading References - Materials Science and Engineering An Introduction, William D.

Callister, Jr.

Lectures Schedule

Weeks Contents

1 Introduction

2 Atomic Structure and Interatomic Bonding

3&4 Structures of Metals and Ceramics

5 Polymer Structures

6 Composites

7&8 Thermal Properties

9&10 Magnetic Properties

11&12 Optical Properties

13&14 Electrical Properties

15 Imperfections in Solids

16-18 Mechanical Properties

19&20 Deformation and Strengthening Mechanisms

21&22 Failure

23&24 Phase Diagrams

25&26 Synthesis, Fabrication, and Processing of Materials

27 Applications of Materials

28 Corrosion and Degradation of Materials

Exams:

There will be two exams (each at the end of first and second semester) and one

final.

Quizzes:

There will be sudden quizzes at each semester.

General Instructions and Commandments:

1- Not eligible for the student to inter the lecture after the lecturer.

2- The student is responsible for any oral or written notes that mention in the

lecture hall.

3- It is not allowed to the student to borrow a pen or calculator or anything

during the exam.

4- It is not allowed to re-exam, just by an official excuse.

Topic No.1

Introduction

Sometimes it is useful to subdivide the discipline of materials science and

engineering into materials science and materials engineering subdisciplines.

Strictly speaking, “materials science” involves investigating the relationships

that exist between the structures and properties of materials. In contrast,

“materials engineering” is, on the basis of these structure–property correlations,

designing or engineering the structure of a material to produce a predetermined

set of properties.

From a functional perspective, the role of a materials scientist is to develop or

synthesize new materials, whereas a materials engineer is called upon to create

new products or systems using existing materials, and/or to develop techniques

for processing materials.

Topic No.2

Atomic Structure and Interatomic Bonding An important reason to have an understanding of interatomic bonding in

solids is that, in some instances, the type of bond allows us to explain a

material’s properties. For example, consider carbon, which may exist as both

graphite and diamond. Whereas graphite is relatively soft and has a “greasy”

feel to it, diamond

is the hardest known material. This dramatic disparity in properties is directly

attributable to a type of interatomic bonding found in graphite that does not

exist in diamond.

Topic No.3&4 Structure of Metals and Ceramics

The properties of some materials are directly related to their crystal

structures. For example, pure and undeformed magnesium and beryllium,

having one crystal structure, are much more brittle (i.e., fracture at lower

degrees of deformation) than are pure and undeformed metals such as gold and

silver that have yet another crystal structure. Furthermore, significant property

differences

exist between crystalline and noncrystalline materials having the same

composition. For example, noncrystalline ceramics and polymers normally are

optically transparent; the same materials in crystalline (or semicrystalline) form

tend to be opaque or, at best, translucent.

Metals Materials in this group are composed of one or more metallic elements

(such as iron, aluminum, copper, titanium, gold, and nickel), and often also

nonmetallic elements (for example, carbon, nitrogen, and oxygen) in relatively

small amounts.3 Atoms in metals and their alloys are arranged in a very orderly

manner and in comparison to the ceramics and polymers, are relatively dense.

With regard to mechanical characteristics, these materials are relatively stiff and

strong, yet are ductile (i.e., capable of large amounts of deformation without

fracture), and are resistant to fracture, which accounts for their widespread use

in structural applications. Metallic materials have large numbers of nonlocalized

electrons; that is, these electrons are not bound to particular atoms. Many

properties of metals are directly attributable to these electrons. For example,

metals are extremely good conductors of electricity and heat, and are not

transparent to visible light; a polished metal surface has a lustrous appearance.

In addition, some of the metals (viz., Fe, Co, and Ni) have desirable magnetic

properties. Figure below is a photograph that shows several common and

familiar objects that are made of metallic materials.

Familiar objects that are made of metals and metal alloys: (from left to right)

silverware (fork and knife), scissors, coins, a gear, a wedding ring, and a nut

and bolt.

Ceramics Ceramics are compounds between metallic and nonmetallic elements;

they are most frequently oxides, nitrides, and carbides. For example, some of

the common ceramic materials include aluminum oxide (or alumina,Al2O3),

silicon dioxide (or silica, SiO2), silicon carbide (SiC), silicon nitride (Si3N4),

and, in addition, what some refer to as the traditional ceramics—those

composed of clay minerals (i.e., porcelain), as well as cement, and glass. With

regard to mechanical behavior, ceramic materials are relatively stiff and

strong—stiffnesses and strengths are comparable to those of the metals . In

addition, ceramics are typically very hard. On the other hand, they are extremely

brittle (lack ductility), and are highly susceptible to fracture . These materials

are typically insulative to the passage of heat and electricity (i.e., have low

electrical conductivities), and are more resistant to high temperatures and harsh

environments than metals and polymers.With regard to optical characteristics,

ceramics may be transparent, translucent, or opaque, and some of the oxide

ceramics (e.g., Fe3O4) exhibit magnetic behavior. Several common ceramic

objects are shown in the photograph of Figure below.

Common objects that are made of ceramic materials: scissors, a china tea cup, a

building brick, a floor tile, and a glass vase.

Topic No.5

Structure of Polymer Polymers include the familiar plastic and rubber materials. Many of them

are organic compounds that are chemically based on carbon, hydrogen, and

other nonmetallic elements (viz.O,N, and Si). Furthermore, they have very large

molecular structures, often chain-like in nature that have a backbone of carbon

atoms. Some of the common and familiar polymers are polyethylene (PE),

nylon, poly(vinyl chloride) (PVC), polycarbonate (PC), polystyrene (PS), and

silicone rubber. These materials typically have low densities, whereas their

mechanical characteristics are generally dissimilar to the metallic and ceramic

materials—they

are not as stiff nor as strong as these other material types . However, on

the basis of their low densities, many times their stiffnesses and strengths on a

per mass basis are comparable to the metals and ceramics. In addition, many of

the polymers are extremely ductile and pliable (i.e., plastic), which means they

are easily formed into complex shapes. In general, they are relatively inert

chemically and unreactive in a large number of environments. One major

drawback to the polymers is their tendency to soften and/or decompose at

modest temperatures, which, in some instances, limits their use. Furthermore,

they have low electrical conductivities and are nonmagnetic.

The photograph in Figure below shows several articles made of polymers

that are familiar to the reader.

Topic No.6

Composites With a knowledge of the various types of composites, as well as an

understanding of the dependence of their behaviors on the characteristics,

relative amounts, geometry/distribution, and properties of the constituent

phases, it is possible to design materials with property combinations that are

better than those

found in the metal alloys, ceramics, and polymeric materials. For example, in

Design Example, we discuss how a tubular shaft is designed that meets

specified stiffness requirements.

Topic No.7&8

Thermal Properties

Materials selection decisions for components that are exposed to

elevated/subambient temperatures, temperature changes, and/or thermal

gradients require the design engineer to have an understanding of the thermal

responses of materials, as well as access to the thermal properties of a wide

variety of materials.

For example, in the discussion on materials that are used for the lead frame

component of an integrated circuit package, we note restrictions that are

imposed on the thermal characteristics of the adhesive material that attaches the

integrated

circuit chip to the leadframe plate. This adhesive must be thermally conductive

so as to facilitate the dissipation of heat generated by the chip. In addition, its

thermal expansion/contraction on heating/cooling must match that of the chip

such that the integrity of the adhesive-chip bond is maintained during thermal

cycling.

Topic No.9&10

Magnetic Properties

An understanding of the mechanism that explains the permanent

magnetic behavior of some materials may allow us to alter and in some cases

tailor the magnetic properties. For example, in Design Example the behavior of

a ceramic magnetic material may be enhanced by changing its composition.

Topic No.11&12

Optical Properties

When materials are exposed to electromagnetic radiation, it is sometimes

important to be able to predict and alter their responses. This is possible when

we are familiar with their optical properties and understand the mechanisms

responsible for their optical behaviors. For example, on optical fiber materials,

we note that the performance of optical fibers is increased by introducing a

gradual variation of the index of refraction (i.e., a graded index) at the outer

surface of the fiber. This is accomplished by the addition of specific impurities

in controlled concentrations.

Topic No.13&14

Electrical Properties Consideration of the electrical properties of materials is often important

when materials selection and processing decisions are being made during the

design of a component or structure. For example, we discuss that are used in the

several components of one type of integrated circuit package. The electrical

behaviors of the various materials are diverse. Some need to be highly

electrically

conductive (e.g., connecting wires), whereas electrical insulativity is required of

others (e.g., the protective package encapsulation).

Topic No.15

Imperfections in Solids

The properties of some materials are profoundly influenced by the

presence of imperfections. Consequently, it is important to have a knowledge

about the types of imperfections that exist and the roles they play in affecting

the behavior of materials. For example, the mechanical properties of pure metals

experience significant alterations when alloyed (i.e., when impurity atoms are

added)—for example, brass (70% copper–30% zinc) is much harder and

stronger than pure copper . Also, integrated circuit microelectronic devices

found in our computers, calculators, and home appliances function because of

highly controlled concentrations of specific impurities that are incorporated into

small, localized regions of semiconducting materials.

Topic No. 16-18

Mechanical Properties It is incumbent on engineers to understand how the various mechanical

properties are measured and what these properties represent; they may be called

upon to design structures/components using predetermined materials such that

unacceptable levels of deformation and/or failure will not occur.

Topic No.19&20

Deformation and Strengthening Mechanisms

With a knowledge of the nature of dislocations and the role they play in

the plastic deformation process, we are able to understand the underlying

mechanisms

of the techniques that are used to strengthen and harden metals and their alloys.

Thus, it becomes possible to design and tailor the mechanical properties of

materials—for example, the strength or toughness of a metal–matrix composite.

Topic No. 21&22

Failure

The design of a component or structure often calls upon the engineer to

minimize the possibility of failure. Thus, it is important to understand the

mechanics of the various failure modes—i.e., fracture, fatigue, and creep—and,

in addition, be familiar with appropriate design principles that may be employed

to prevent in-service failures.

Topic No.23&24

Phase Diagram

One reason that a knowledge and understanding of phase diagrams is

important to the engineer relates to the design and control of heat-treating

procedures; some properties of materials are functions of their microstructures,

and, consequently, of their thermal histories. Even though most phase diagrams

represent stable (or equilibrium) states and microstructures, they are

nevertheless useful in understanding the development and preservation of

nonequilibrium structures and their attendant properties; it is often the case that

these properties are more desirable than those associated with the equilibrium

state. This is aptly illustrated by the phenomenon of precipitation hardening.

Topic No.25&26

Synthesis, Fabrication, and Processing of Materials

It is important for the engineer to realize how the applications and

processing of ceramic materials are influenced by their mechanical and thermal

properties, such as hardness, brittleness, and high melting temperatures. For

example, ceramic pieces normally cannot be fabricated using conventional

metal forming techniques. they are often formed using powder compaction

methods, and subsequently fired (i.e., heat treated).

Topic No.27

Applications of Materials

Engineers are often involved in materials selection decisions, which

necessitates that they have some familiarity with the general characteristics of a

wide variety of metals and their alloys (as well as other material types). In

addition, access to databases containing property values for a large number of

materials may be required.

Topic No. 28

Corrosion and Degradation of Materials

With a knowledge of the types of and an understanding of the

mechanisms and causes of corrosion and degradation, it is possible to take

measures to prevent

them from occurring. For example, we may change the nature of the

environment, select a material that is relatively nonreactive, and/or protect the

material from appreciable deterioration.