Chapter 1 -

ME -254

MATERIALS ENGINEERING

Dr. Md Irfanul Haque Siddiqui (Irfan)

Department of Mechanical Engineering

King Saud University, Riyadh, Saudi Arabia

Email: msiddiqui2.c@ksu.edu.sa

Office: 2C-69, Building 3

College of Engineering

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Chapter 1 -

MSE XXX: Introduction to

Materials Science & EngineeringCourse Objective...

Introduce fundamental concepts in Materials

Science & Engineering

You will learn about:• material structures

• how structure dictates properties

• how processing can change structure

This course will help you to:• use materials properly

• realize new design opportunities

with materials

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Chapter 1 -

Required text:• Materials Science and Engineering:

An Introduction, W.D. Callister, Jr. and D.G.

Rethwisch, 9th edition, John Wiley and Sons, Inc.

COURSE MATERIALS (with text)

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Chapter 1 -

Course Website: https://fac.ksu.edu.sa/msiddiqui2c• Syllabus

• Lecture notes

WEBSITES

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Chapter 1 -

GRADING

Midterm #1 XX%Tentatively scheduled for: Week 6th, Thursday 6/7 PM

Material covered:

Midterm #2 XX%Tentatively scheduled for: Week 12th, Thursday 6/7 PM

Material covered:

Final XX%Tentatively scheduled for:

Material covered:

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Chapter 1 -

Chapter 1: Introduction to

Materials Science & Engineering

ISSUES TO ADDRESS...

• What is materials science and engineering?

• Why are materials important?

• Why is it important for engineers to understand

materials ?

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Chapter 1 -

What is Materials Science & Engineering?

• Materials science– Investigate relationships between structures and

properties of materials

– Design/develop new materials

• Materials engineering– Create products from existing materials

– Develop materials processing techniques

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Chapter 1 -

Why Are Materials Important?

• Materials drive advancements in our society – Stone Age

– Bronze Age

– Iron Age

• What is today’s material age?– Silicon (Electronic Materials) Age?

– Nanomaterials Age?

– Polymer Age?

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Chapter 1 -

Why is it Important for Engineers to

Understand Materials?

• Products/devices/components that engineers design are all made of materials

• To select appropriate materials and processing techniques for specific applications engineers must– have knowledge of material properties and

– understand the structure-property relationships

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Chapter 1 -

• Processing (e.g., cooling rate of steel from high

temperature) affects structure (microstructure)

Data obtained from Figs. 10.32(a) and

10.33 with 0.4 wt% C composition, and

from Fig. 11.18, Callister & Rethwisch 10e.

Micrographs adapted from (a) Fig. 10.19;

(b) Fig. 9.30; (c) Fig. 10.34; and (d) Fig.

10.22, Callister & Rethwisch 10e. (Figures

10.19, 10.22, & 10.34 copyright 1971 by United

States Steel Corporation. Figure 9.30 courtesy

of Republic Steel Corporation.)

Relationships Among Processing,

Structure, & Properties

Ha

rdn

ess (

BH

N)

Cooling Rate (ºC/s)

100

200

300

400

500

600

0.01 0.1 1 10 100 1000

(d)

30 μm(c)

4 μm

(b)

30 μm

(a)

30 μm

• Structure in turn effects hardness

Property

Processing

Structure

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Chapter 1 -

Types of Materials• Metals:

– Strong, ductile

– High thermal & electrical conductivities

– Opaque, reflective

• Polymers/plastics: compounds of non-metallic elements

– Soft, ductile, low strengths, low densities

– Low thermal & electrical conductivities

– Opaque, translucent or transparent

• Ceramics: compounds of metallic & non-metallic elements (oxides, carbides, nitrides, sulfides)

– Hard, Brittle

– Low thermal & electrical conductivities

– Opaque, translucent, or transparent

Composites/ Semi-conductors/ biomaterials/ smart materials/ nanomaterials

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Chapter 1 -

1. For a Specific Application Determine Required Properties

• To provide required set of properties

• To produce component having desired shape and size

• Example techniques: casting, mechanical forming, welding,

heat treating

• Properties: mechanical, electrical, thermal,

magnetic, optical, deteriorative.

2. From List of Properties Identify Candidate Material(s)

3. Best Candidate Material Specify Processing technique(s)

Materials Selection

Engineers often solve materials selection problems.

Procedure:

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Chapter 1 -

Material Property Types

• Mechanical

• Electrical

• Thermal

Properties of materials fall into six categories as

follows:

• Magnetic

• Optical

• Deteriorative

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Chapter 1 -

Mechanical Properties

Fig. 10.31, Callister & Rethwisch 10e. [Data taken from Metals Handbook: Heat

Treating, Vol. 4, 9th edition, V. Masseria

(Managing Editor), 1981. Reproduced by

permission of ASM International, Materials Park,

OH.]

80

160

240

320

wt%C0 0.5 1

Brinell

hard

ness

Affect of carbon content on the hardness of a

common steel:

• Increasing carbon content increases hardness of steel.

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Chapter 1 -

Electrical Properties

Factors that affect electrical resistivity – for copper:

• Increasing impurity content (e.g., Ni) increases resistivity.

• Deformation increases resistivity.

Fig. 18.8, Callister & Rethwisch 9e. [Adapted from: J.O. Linde, Ann Physik 5, 219

(1932); and C.A. Wert and R.M. Thomson,

Physics of Solids, 2nd edition, McGraw-Hill

Company, New York, 1970.]

T (°C)-200 -100 0

1

2

3

4

5

6

Resis

tivity,

ρ

(10

-8O

hm

-m)

0

• Increasing temperature increases resistivity.

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Chapter 1 -

Thermal Conductivity – measure of a material’s ability to

conduct heat

Thermal Properties

Composition (wt% Zinc)

Therm

al C

onductivity

(W/m

-K)

400

300

200

100

00 10 20 30 40

• Increasing impurity content (e.g., Zn in Cu) decreases

thermal conductivity.

Fig. 19.4, Callister & Rethwisch 10e. [Adapted from Metals Handbook: Properties

and Selection: Nonferrous alloys and Pure

Metals, Vol. 2, 9th ed., H. Baker, (Managing

Editor), ASM International, 1979, p. 315.]

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Chapter 1 -

Thermal Properties (continued)

Highly porous materials are

poor conductors of heat

Court

esy o

f Lockheed A

ero

space C

era

mic

s

Syste

ms, S

unnyvale

, CA

100μm Court

esy o

f Lockheed M

issiles a

nd S

pace

Com

pany, In

c.

• Ceramic Fibers:– significant void space

– low thermal conductivity

Material used for space

shuttle

• Demonstration:– low thermal conductivity

of this material

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Chapter 1 -

Magnetic Properties• Magnetic Permeability

vs. Composition:-- Adding 3 atomic % Si makes

Fe a better recording medium!

Adapted from C.R. Barrett, W.D. Nix, and

A.S. Tetelman, The Principles of Engineering

Materials, Fig. 1-7(a), p. 9, 1973.(Electronically reproduced by permission of Pearson

Education, Inc., Upper Saddle River, New Jersey.)

Fig. 20.23, Callister & Rethwisch 10e.(Courtesy of HGST, a Western Digital Company.)

• Magnetic Storage:-- Recording medium is

magnetized by recording

write head.

Magnetic Field

Magnetizatio

n

Fe+3%Si

Fe

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Chapter 1 -

• The light transmittance of some materials depend on their

structural characteristics:(S

pecim

en p

repara

tion, P

.A. Lessin

g)

Optical Properties

Aluminum oxide single

crystal (high degree of

perfection)—is optically

transparent

Aluminum oxide

polycrystalline material

(having many small

grains)—is optically

translucent

Aluminum oxide

polycrystalline

material having some

porosity—is optically

opaque

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Chapter 1 -

Deteriorative Properties

• Small cracks formed in steel bar that was simultaneously

stressed and immersed in sea water

- Form of stress-corrosion cracking

Fig. 17.21, Callister & Rethwisch 10e. (from Marine Corrosion, Causes, and Prevention, John Wiley and Sons, Inc., 1975.)

Cracks

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Chapter 1 -

Deteriorative Properties (cont.)

• For stress-corrosion cracking, rate of crack growth is

diminished by heat treating

Adapted from Fig. 11.20(b), R.W.

Hertzberg, "Deformation and

Fracture Mechanics of Engineering

Materials" (4th ed.), p. 505, John

Wiley and Sons, 1996. (Original

source: Markus O. Speidel, Brown

Boveri Co.)“heat treated”

Cra

ck G

row

th R

ate

(m

/s) “as-received”

load

10-10

10-8

For Aluminum alloy 7178 that is stressed while immersed in a

saturated aqueous NaCl solution, crack growth rate is reduced by

heat treating (160C for 1 h prior to testing). 21

Chapter 1 -

Example of Materials Selection:

Artificial Hip Replacement

• Anatomy of a

human hip joint and

adjacent skeletal

features

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Chapter 1 -

Materials: Artificial Hip Replacement

(cont.)

Hip joint problems can be painful and disabling

• Joint deterioration (loss of cartilage) as one ages

• Joint fracture

X-ray of normal hip joint X-ray of fractured hip joint

arrows point to

ends of fracture line

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Chapter 1 -

Materials: Artificial Hip Replacement

(cont.)

• Damaged and diseased hip joints can be

replaced with artificial ones

• Materials requirements for artificial joints

– Biocompatible – minimum rejection by surrounding

body tissues

– Chemically inert to body fluids

– Mechanical strength to support forces generated

– Good lubricity and high wear resistance between

articulating surfaces

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Chapter 1 -

Materials: Artificial Hip Replacement

(cont.)

• Materials used- Femoral stem — titanium or CoCrMo alloy

- Head (Ball) — CoCrMo alloy or Al2O3 (ceramic)

- Shell — titanium alloy

- Liner — polyethylene (polymer) or Al2O3 (ceramic)

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Chapter 1 -

SUMMARY

• Appropriate materials and processing decisions

require engineers to understand materials and their

properties.

• Materials' properties depend on their structures;

structures are determined by how materials are

processed

• In terms of chemistry the three classifications of

materials are metals, ceramics, and polymers

• Most properties of materials fall into the following six

categories: mechanical, electrical, thermal, magnetic,

optical, and deteriorative.

• An important role of engineers is that of materials

selection.

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