Materials Science and Engineering 01

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Engineering ScienceEngineering Science(ENG 232)(ENG 232)

Materials Science andMaterials Science and

Engineering Engineering

LECTURE NOTE 1LECTURE NOTE 1



For Your Information For Your Information

Lecturer:

Prof. San-Qiang Shi (石三强)

Dept. of Mechanical Engineering

Office: FG603Tel: 2766-6663Email: [email protected]

Tutors:Ms. Maggie Leung

Ms. Iris Chan

Mr. Truman Xiao



References References

Textbook: Materials Science and Engineering - An

Introduction (7th edition), by William D. Callister, Jr., JohnWiley & Sons, 2007. TA403.C23 2007

References:(1) W.D. Callister, Fundamentals of Materials Science and Engtineering:

an integrated approach, John Wiley & Sons, 2008. TA403.C227 2008(2) D. R. Askeland, The Science and Engineering of Materials,

3nd Ed., PWS-Kent Pub. Co., 1994.

(3) W. F. Smith, Principles of Materials and Engineering,

3nd Ed., McGraw-Hill, Inc., 1996.(4) W. F. Smith, Foundations of Materials Science and Engineering, 3th

Ed, McGraw-Hill, Inc., 2003

(5) J.F. Shackelford, Introduction to Materials Science for Engineers, 4th

Ed., Prentice Hall International, Inc., 1996



Course Arrangement Course Arrangement Contents of the Subject:

Energy Utilization (15 hours)

(taught by Dr. KL Chan in weeks 1-5)

Materials Science & Engineering (will be taught by

Prof. SQ Shi in weeks 6 - 14)



Course Arrangement Course Arrangement

Contents of the lecturesContents of the lectures::

Introduction (Week 6)

Interatomic Bonding & Structure of Crystalline (Week 6 - 7)Mechanical Properties of Materials (Weeks 7 - 8)Failure of Materials (Week 9)Dislocations and Strengthening Mechanisms (Week 10)Phase Diagrams (Week 11)Optical and Electrical Properties of Materials (Week 12)Manufacturing Technology of Materials (Week 12)Applications and Selection of Engineering Materials

(Week 13)

Ecological Design (Week 14)Review (Week 14)

Tutorial

Lab: Tensile Strength of Metallic and Plastic Materials



Tutorial Arrangement Tutorial Arrangement

Time: To be scheduled

Room: As assigned



Lab. Arrangement Lab. Arrangement

Lab experiments will start from week 10 and be performed in group. The lab work includes:

reading before the lab session

lab work

group lab report (due two weeks after the

lab session)

Time: To be scheduled

Room: DE006



Grading Policy Grading Policy

Coursework: 40%

Final examination: 60%



Objectives:

This part aims:

1. to enable students to establish a broad knowledge

base on the atomic structure and properties of

materials with an emphasis on using this knowledge

to solve engineering problems.

2. to provide a basic understanding on relationship

between material properties and manufacturingprocesses so that students are able to select those

that are appropriate taking into consideration green

design and environmental issues.



Student Learning Outcomes:

Upon satisfactory completion of the subject, students

are expected to achieve the following learning

outcomes:

1. To be able to apply the knowledge of materials

science to analyse and solve basic engineeringproblems related to stress, strain and fracture of

materials.

2. To be able to select appropriate materials and

manufacturing processes for different products

taking into consideration of issues in cost, quality

and environmental concerns.



Introduction Introduction

Questions:

Why should I study materials science &engineering?

What materials are available to me?

Which material is better? - competition among materials

Which material do I now select for a

particular application?

What is the future trends in materials usage?



What are Materials?

• Materials may be defined as substance of

which something is composed or made.

• We obtain materials from earth crust andatmosphere.

• Examples :-• Silicon and Iron constitute 27.72 and

5.00 percentage of weight of earths

crust respectively.

• Nitrogen and Oxygen constitute 78.08

and 20.95 percentage of dry air by

volume respectively.



Question 1Question 1

Why should I study materials science &Why should I study materials science &engineering?engineering?



Engineering MaterialsEngineering Materials - -

the Base of Modern Technologythe Base of Modern Technology

End ApplicationsManufacture

Existing Materials New Materials

Design Material Selection New Ideas



• Production and processing of materials constitute

a large part of our economy.• Engineers choose materials to suite design.

• New materials might be needed for some new

applications.

– Example :

– High temperature resistant materials. – Space station and Mars Rovers should sustain

conditions in space.

* High speed, low temperature, strong but light.

• Modification of properties might be needed forsome applications.

– Example :- Heat treatment to modify Properties.



Materials Science and Engineering

• Materials science involves investigation of relationship betweenstructures and properties of materials.

• Materials engineering involves designing and engineering the

structure of materials to produce desired properties.

What is structure?

- Structure is the arrangement of atoms.

- Subatomic structure is arrangement of electrons within eachindividual atom, and their interactions with nuclei.

What is property?

- Property is a trait in terms of the kind and magnitude ofresponse to a specific imposed stimulus.

- Six groups of properties: mechanical, electrical, thermal,

magnetic, optical, and deteriorative.



Why Study Materials Science and Engineering

An engineer has to select materials at various stages of his/her

engineering.

How does one select “proper” materials

- select materials that fit the service conditions

- select materials that resist deterioration

- select materials that are economical

How can one know the selection criteria

- knowledgeable in materials science and engineering(that is processing-structure-property-performance

relationship)



Question 2Question 2What materials are available to me?What materials are available to me?



MATERIALS MATERIALS

FOR ENGINEERING FOR ENGINEERING

TYPES OF MATERIALS

METALS

CERAMICS AND GLASSES

POLYMERS

COMPOSITES

SEMICONDUCTORS

SMART MATERIALS

NANOMATERIALS



METALS METALS

Characteristics:

Strong & deformable.

Good ductility.

High electrical andthermal conductivity

Not transparent to

visible light.

Metallic lustrous

appearance.



58 59 60 61 62 63 64 65 66 67 68 69 70 71

Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

90 91 92 93 94 95 96 97 98 99 100 101 102 103

Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lw

I A O

1 2

H II A IIIA IVA V A VIA VIIA He

3 4 5 6 7 8 9 10

Li Be B C N O F Ne

11 12 VIII 13 14 15 16 17 18

Na Mg IIIB IVB V B VIB VIIB I B IIB Al Si P S Cl Ar

19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36

K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr

37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54

Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe

55 56 57 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86

Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn

87 88 89

Fr Ra Ac

METALS METALS

Metallic materials are normally

combinations of metallic

elements



CERAMICS CERAMICS

Characteristics:

High strength and

low ductility.

High chemical &temperature stability.

Good insulators of

electrical current &heat.

High stiffness, low

coefficient ofexpansion.



CERA CERA MICS MICS

Ceramics are compounds between metallic

and nonmetallic elements.

58 59 60 61 62 63 64 65 66 67 68 69 70 71


90 91 92 93 94 95 96 97 98 99 100 101 102 103

Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lw

I A O

1 2


3 4 5 6 7 8 9 10

Li Be B C N O F Ne

11 12 VIII 13 14 15 16 17 18

Na Mg IIIB IVB V B VIB VIIB I B IIB Al Si P S Cl Ar

19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr

37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54


55 56 57 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86


87 88 89

Fr Ra Ac



POLYMERS POLYMERS

Characteristics:

Wide spectrum of strength &ductility .

Lightweight.

Poor conductors of electricalcurrent & heat.

Relatively low softening or

decomposition temperatures.

High coefficient of expansion.



POLYMERS POLYMERS

Polymers are organic compounds consisting

of long molecular chains or networks.

58 59 60 61 62 63 64 65 66 67 68 69 70 71


90 91 92 93 94 95 96 97 98 99 100 101 102 103Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lw

I A O

1 2


3 4 5 6 7 8 9 10

Li Be B C N O F Ne

11 12 VIII 13 14 15 16 17 18

Na Mg IIIB IVB V B VIB VIIB I B II B Al Si P S Cl Ar

19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36


37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54


55 56 57 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86


87 88 89

Fr Ra Ac



Room-temperature Mechanical Properties of Some of the More Common Polymers

POLYMERS POLYMERS



COMPOSITES COMPOSITES

Composites are mixtures of two or more materials.

The components can be physically identified by an

interface between them.

Property Combinations of each components




Applications

Of Composites



SEMICONDUCTORS SEMICONDUCTORS

Intermediate electrical

conductivity.

Electrical characteristics are

extremely sensitive to chemical

purity.



SEMI SEMI CONDUC CONDUC TORSTORS• Elemental semiconductors are Si, Ge, Sn.

• Semiconducting compounds are composed of

pairs of elements from columns III & V (e.g.

GaAs) or from columns IIB & VI (e.g. CdS)

58 59 60 61 62 63 64 65 66 67 68 69 70 71


90 91 92 93 94 95 96 97 98 99 100 101 102 103Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lw

I A O

1 2H II A IIIA IVA V A VIA VIIA He

3 4 5 6 7 8 9 10

Li Be B C N O F Ne

11 12 VIII 13 14 15 16 17 18

Na Mg IIIB IVB V B VIB VIIB I B II B Al Si P S Cl Ar19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36


37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54


55 56 57 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn

87 88 89

Fr Ra Ac



SmartSmart MaterialsMaterials andand StructuresStructures



Typical Smart Materials:

•Ferro/Piezo-electric Materials

•Shape Memory Alloys

•Optical Fiber Sensors

•Shape Memory polymers

•Electrical Flow

SmartSmart MaterialsMaterials andand StructuresStructures



ProductsProductswith Smartwith Smart

MaterialsMaterialsApplications of shape memory alloys



Shape Recovery

Force Recovery

Motor-free

Mechanism

Applications of shape memory alloys



NanoNano MaterialsMaterials andand TechnologyTechnology

Nano-conductive

channel

Nano-guiter

Nano-gear Nano-actuator(Carbon nanotube)

Fuel-cell(Hydrogen storage)



• What have been done…

Micro-chips

Micro-motors



Dreams…

Nano-pump Nano-bearings

Nano-arm

Nano-chips ?




Which material is better?Which material is better?



Competition among MaterialsCompetition among Materials

Properties Vs. Costs Properties Vs. Costs



For some applications onlyFor some applications only

certain materials can meet thecertain materials can meet theengineering requirements.engineering requirements.




Which material should I select for aWhich material should I select for a

particular application? particular application?

S l i fS l ti f



Selection ofSelection of

Materials Materials

Selection of material

can be simple and

obvious, for example:

S E M

I C O N D U

C T O R S

S E M

I C O N D U

C T O R S



Selection of Materials Selection of Materials

But, most choices are less obvious,

e.g. selecting material for a commercialgas cylinder.

Critical property requirement:

Pressure = 14 MPa




ASTM A414 - Grade G

which is Iron

+ 0.31wt% C max.

+ 1.35wt% Mn max.

+ 0.035wt% P max.

+ 0.04wt% S max.

Metals

Ceramics

Polymers

Semiconductors

Composites

Strength

Ductility

Cost

Metals

Ferrous Nonferrous

Irons steels

Carbon & High-alloy steelslow-alloy steels




Another example:

selecting material for anaerospace pressure vessel.

Critical property requirement:

Light weight




Composites

Strength

Ductility

Low

Density

Ceramics

Metals

Polymers

Semiconductors

Composites

Fiber-reinforced Aggregate-reinforced

Synthetic fibers Natural fibers

Polymer Metal Ceramics Glass

fibers fibers fibers fibers

Kevlar 49 aramid fibers

wound in an epoxy matrix




What is the future trends in materialsWhat is the future trends in materials research and application? research and application?

F T d



Future Trends

• Metallic Materials

Production follows economy closely.

Alloys may be improved by better chemistry andprocess control.

New aerospace alloys being constantly researched.

o Aim: To improve temperature and corrosionresistance.

o Example: Nickel based high temperature superalloys.

New processing techniques are investigated.o Aim: To improve product life and fatigue properties.

o Example: Isothermal forging, Powder metallurgy.

Metals for biomedical applications

F T d



Future Trends

• Polymeric (Plastic Materials)

Fastest growing basic material (9%

per year). After 1995 growth rate decreased

due to saturation.

Different polymeric materials canbe blend together to produce new

plastics.

Search for new plastic continues.

F t T d



Future Trends

• Ceramic Materials

New family of engineering ceramics are produced

last decade New materials and applications are constantly

found.

Now used in auto and biomedical applications. Processing of ceramics is expensive.

Easily damaged as they are highly brittle.

Better processing techniques and high-impactceramics are to be found.

F t T d



Future Trends

• Composite Materials

Fiber reinforced plastics are primary

products. On an average 3% annual growth from

1981 to 1987.

Annual growth rate of 5% is predictedfor new composites such as Fiberglass-

Epoxy and Graphite-Epoxy

combinations.

Commercial aircrafts are expected to

use more and more composite materials.

F t T d



Future Trends

• Electronic Materials

Use of electronic materials such as silicon

increased rapidly from 1970. Electronic materials are expected to play

vital role in “Factories of Future”.

Use of computers and robots will increaseresulting in extensive growth in use of

electronic materials.

Aluminum for interconnections inintegrated circuits might be replaced by

copper resulting in better conductivity.

F t T d



Future Trends

• Smart Materials : Change their properties by

sensing external stimulus.

Shape memory alloys: Strained material revertsback to its original shape above a critical

temperature.

Used in heart valves and to expand arteries.

Piezoelectric materials: Produce electric field when

exposed to force and vice versa.

Used in actuators and vibration reducers.

MEMS d N t i l



MEMS and Nanomaterials

• MEMS: Microelectromechanical systems.

Miniature devices

Micro-pumps, sensors

• Nanomaterials: Characteristic length < 100 nm

Examples: ceramics powder and grain size < 100nm

Nanomaterials are harder and stronger than bulk

materials. Have biocompatible characteristics ( as in

Zirconia)

Transistors and diodes are developed on ananowire.



Modern Materials’ Needs

• Nuclear materials: fuels, containment structures, etc.

• Light materials: parts of automobiles, aircraft, trains, etc.

• High T materials: engine components

• Energy conversion materials: solar cells, hydrogen storage cells

• Jobs for you:

- Be aware of the fundamental materials- Understand basic functions and properties of materials

- Know 3 key components in materials selection



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