Chapter 1-

Reading: Chapter 1 & 2. Class notes are in:WEB SITE

HW # 1: due Thursday, September 4, 2008: Problems 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7

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ANNOUNCEMENTS

Chapter 1-

CHEN 313: Materials Science and Engineering

Course Objective...Introduce fundamental concepts in Materials S&T

You will learn about:• material structure• how structure dictates properties• how processing can change structure

This course will help you to:• use materials properly• realize new design opportunities

with materials

a

Chapter 1-

Lecturer: Dr Jorge Seminario

Time: Tu&Th 2:20-3:35 pm

Make up or additional classes: Tu or Th 7 PM (TBA)

Location: CHEN 106

b

LECTURES

Chapter 1-

Teaching Assistants will grade your homework and exams

Notice: goals of exams and HW are different

One teaching assistant!Three graders!!!

d

TEACHING ASSISTANTSwe have one now!!

Chapter 1-

In my office: Wednesdays: 4:30-5:20 PMThursdays: 3-4 PM

In cyber-space: 24-7

Due to the large number of students virtual office hours will be preferred

Responses to all studentse

OFFICE HOURS

Chapter 1-• other books

Required text:Fundamentals of Materials Science and Engineering: An Integrated Approach3rd Edition

W.D. Callister, Jr. and D. G. RethwischJohn Wiley and Sons, Inc. (2007).

Both book and accompanying CD-ROM are useful.

Other Materials:• papers

COURSE MATERIAL

Chapter 1-

exam # 1 15%

exam #2 15%

exam #3 15%

final 40%

g

GRADING

Homework, class participation: 15%projects, group work, quizes, etc.

Chapter 1-

Materials are... engineered structures...not blackboxes!

Structure...has many dimensions...

Structural feature Dimension (m)atomic bondingmissing/extra atomscrystals (ordered atoms)second phase particlescrystal texturing

< 10-10 10-10

10-8-10-110-8-10-4> 10-6

1

CHAPTER 1: MATERIALS SCIENCE & ENGINEERING

Chapter 1-

Introduction• Materials Science. Investigation of the relationships

between the structures and properties of materials– How do the arrangement of a materials components (e.g.

atoms, etc.) influence its properties (e.g. does it conduct electrons or not)?

• Materials Engineering. Designing the structure of a material so that it has desired properties.

UNCLASSIFIED

Future Force Warrior: Technical Challenges for Dismounted Soldier

Substantial Weight Savings/Low Bulk

Ballistic, Chem/Bio, EM Protection

Integrated Combat Suit

Electro-Textile Power/Data Body LAN, Embedded Sensors & Antenna Array

NanoElectronics and NanoPhotonicsEnabling Technology for the Future Force Warriors

Enabled by Nanomaterials Electro-TextilesElectro-TextilesCompact PowerCompact Power

Micro-Cooling & HeatingMicro-Cooling & HeatingEmbedded Nano-Micro SensorsEmbedded Nano-Micro SensorsChem-Bio Detection/ProtectionChem-Bio Detection/Protection

Communications/Data Body LANCommunications/Data Body LANSignature ManagementSignature Management

Durable Layer Durable Layer with Advanced with Advanced Camouflage Camouflage

Selectively Permeable Selectively Permeable Chemical Biological Chemical Biological BarrierBarrier

Spacer Fabric for Spacer Fabric for Conditioned Air FlowConditioned Air Flow

Soft Body Armor Soft Body Armor

Embedded Embedded Sensors & Sensors & Data/Power Data/Power BusBus

Ambient Air Ambient Air FlowFlow

Enhance warrior’s ability to fight and survive in any mission/environment.

Integrate functions and enable “plug-and-play” capabilities tailored to mission.

Physical/electrical interfaces for Future Force Warrior equipment.

UNCLASSIFIED

Chapter 1-

Chapter 1-

Chapter 1-

Introduction

• Another view of this course:– Macroscopic versus microscopic

• Engineers typically are interested in macroscopic properties (e.g. heat capacities, viscosity, fracture strength, etc.)

• Scientists often describe things in microscopic terms (e.g. bond strength, orbital theory, etc.)

• However, recent trends tend to mix both approaches: Engineers and Scientists both look at micro and macroscopic properties and try to understand the connection between them

– In this class I am going to, whenever possible, show the interrelationship between microscopic and macroscopic properties

Chapter 1-

Introduction

• Processing/Structure/Properties/Performance– They are interrelated!

Processing Structure Properties Performance

• As engineers you are probably more tuned into processing and performance• However, how processing influences the structure is critical• Why? This will influence the material properties, which of

course affect its performance!

Chapter 1-

Introduction

• What do I mean by structure?– Structure is related to the arrangement of a material’s

components• This could be on any length scale• Atomic, nano-, micro-, macro-

– All of these length scales matter!

Types of Carbon (just plain old carbon!)

Diamond Graphite C60 - Fullerene Carbon nanotubes

Chapter 1-

Introduction

• Properties

– How the material behaves in terms of the kind and magnitude of response to an imposed stimulus

– What are the stimuli?• Temperature• Magnetic field• Electric field

– material properties are typically defined independent of material shape and size!

– However… what about nanosize objects?

Chapter 1-

Introduction

• Properties– For the purposes of this course we will group properties into six

categories• Mechanical• Electrical• Thermal• Magnetic• Optical• Deteriorative

Chapter 1-

Introduction

Property Example (Physics) Example Properties

Mechanical Rate of material deformation to an applied load

Elastic modulus

Electrical Response of material to an applied electrical field

Electrical conductivity

Thermal Material expansion/contraction with change in temperature

Heat capacity, thermal

conductivity

Magnetic Response of a material to an applied magnetic field

Magnetic susceptibility

Optical Response of material to electromagnetic radiation

Refractive index

Deteriorative Rate of decomposition of material (often in presence of acid, etc.)

Corrosion rate

Chapter 1-

Introduction

• Processing Structure Properties

Same material – aluminum oxide. Depending on structure (which is influenced by processing) materials are transparent, translucent, opaque

Chapter 1-

Introduction

• Classification of Materials– In materials science there have typically been three

categories of materials• Metals• Ceramics• Polymers

– I will also use this convention; in addition there are several others that are variants (or combinations) of the three

• Composites• Semiconductors• Biomaterials

Material Categories

• Materials can be divided into five broad categories:– Ceramics– Polymers (plastics)– Composite materials– Metals and alloys– Liquids and gases

Material Categories• Materials can be divided into five broad categories:

– Ceramics– Polymers– Composite materials– Metals and alloys

• Provide high strength, stiffness, relatively easy to process– Liquids and gases Metal and alloys used for the construction

of bridges and ships

Chapter 1-

Introduction

• Metals– Defining characteristic of a metal

• High number of delocalized electrons– What does this mean? -- The electrons (outer valence e-’s of

the various atoms) are not bound to particular atoms– Impact delocalization has on properties? Metals are:

» Good conductors of heat and electricity» Not transparent to visible light» Mechanically they are strong, yet deformable

• Examples – silver, gold, platinum, copper

Chapter 1-

Introduction

• Ceramics– “Between” metallic and nonmetallic compounds

• Oxides, nitrides, and carbides• These materials are typically insulators of heat and electricity• More resistant to high temperature (e.g. high melting points)

and harsh environments (e.g. pH) than metals• Mechanically – ceramics are hard but brittle

• Examples: silica (glass), alumina, silicon nitride

Material Categories

• Materials can be divided into five broad categories:– Ceramics

• Fusion of powders (e.g, aluminum oxide) under high pressure and temperature. Properties: High temperature resistance, relatively high strength, brittle, hard, corrosion resistant

– Polymers (plastics)– Composite materials– Metals and alloys– Liquids and gases

Chapter 1-

Introduction

• Polymers– Plastics and rubber materials

• Macromolecules – generally formed from carbon, nitrogen, oxygen and hydrogen (chon systems or molecules)

• there are polymers that contain metals• Usually have low densities• Can be extremely flexible• Not stable at high temperatures typically

• Examples: polyethylene, polystyrene, polyamide (Nylon®)

*CH2

H2C

*n

*CH

H2C

*n

*

HN

R

HN R'

O

*

O

n

Material Categories

• Materials can be divided into five broad categories:– Ceramics– Polymers

• Include plastics and rubbers. Properties: Easy to fabricate, low weight, low cost, good insulators, low temperature resistance, weak, compliant and durable

– Composite materials– Metals and alloys– Liquids and gases

Chapter 1-

Introduction

• Composites– Exactly what it sounds like: a new material that

consists of more than one component• Fiberglass – glass fibers embedded in a polymeric matrix• Idea – get desirable features of each material component• Complicated though – does not always work out as well as

you’d like

Material Categories• Materials can be divided into five broad categories:

– Ceramics– Polymers– Composite materials

• Combination of different materials (reinforcing component and binder). Properties: High strength to weight ratios, low weight, high stiffness, brittle

– Metals and alloys– Liquids and gases

Experimental aircraft: Entire body composed of composites

Chapter 1-

Introduction

• Semiconductors– Materials with electrical properties intermediate of a

metal (good conductor) and a ceramic (good insulator)– Silicon is the essential example – computer chips

• Key to use of semiconductors is the extremely precise control of dopant atoms that are used to manipulate the conducting properties

Chapter 1-

Introduction

• Biomaterials– Use of the above materials in life science applications– Key point: the material must not lead to an adverse

physiological reaction– Hip implants are the big success story here

Material Categories

• Materials can be divided into five broad categories:– Ceramics– Polymers– Composite materials– Metals and alloys– Liquids and gases

• Play a major role in heat transfer (e.g, radiator), hydraulic and pneumatic systems, lubrication

ex: hardness vs structure of steel • Properties depend on structure

Data obtained from Figs. 10.21(a)and 10.23 with 4wt%C composition,and from Fig. 11.13 and associateddiscussion, Callister 6e.Micrographs adapted from (a) Fig.10.10; (b) Fig. 9.27;(c) Fig. 10.24;and (d) Fig. 10.12, Callister 6e.

ex: structure vs cooling rate of steel • Processing can change structure

Structure, Processing, & Properties

Cooling Rate (C/s)100200300400500600

0.01 0.1 1 10 100 1000

(a)

30m

(b)

30m

(d)

30m(c)

4m

Brin

ell Hardness N

umbe

r (BH

N)

Brinell hardness test

(BHN)

Chapter 1-

1. Pick Application Determine required Properties

2. Properties Identify candidate Material(s)

3. Material Identify required ProcessingProcessing: changes structure and overall shapeex: casting, sintering, vapor deposition, doping forming, joining, annealing.

Properties: mechanical, electrical, thermal,magnetic, optical, deteriorative.

Material: structure, composition.

3

The Materials Selection Process

Material Selection Considerations

• Properties, Processing, Cost, Availability• Importance of each one depends on application:

– Military and Space applications pushing material properties and processing to their limits more important than cost

Chapter 1-

Advances in materials(see pdf in website)

Materials Process Design and Control LaboratoryMaterials Process Design and Control Laboratory

CCOORRNNEELLLL U N I V E R S I T Y

MATERIALS DESIGN FRAMEWORK

Machine learning schemes

Microstructure Information library

Accelerated Insertion of new

materials

Optimization of existing

materials

Tailored application specific material

properties

Virtual process simulations to

evaluate alternate designs

Computational process design

simulator

Virtual materials design

framework

Materials Process Design and Control LaboratoryMaterials Process Design and Control Laboratory

CCOORRNNEELLLL U N I V E R S I T Y

DESIGNING MATERIALS WITH TAILORED PROPERTIES

Micro problem driven by the velocity gradient L

Macro problem driven by the macro-design

variable βBn+1

Ω = Ω (r, t; L)~Polycrystal

plasticityx = x(X, t; β)

L = L (X, t; β)ODF: 1234567

L = velocity gradient

Fn+1

B0

Reduced Order Modes

Data mining techniques

Multi-scale Computation

Design variables (β) are macrodesign variables Processing sequence/parameters

Design objectives are micro-scale

averaged material/processproperties

Database

Chapter 1-

T (°C)-200 -100 0

Cu + 3.32 at%Ni

Cu + 2.16 at%Ni

deformed Cu + 1.12 at%Ni

123456

Resis

tivity

,

(10-

8 Oh

m-m

)

0

Cu + 1.12 at%Ni

“Pure” Cu

• Electrical Resistivity of Copper:

• Adding “impurity” atoms to Cu increases resistivity.• Deforming Cu increases resistivity.

4

Adapted from Fig. 18.8, Callister 6e.(Fig. 18.8 adapted from: J.O. Linde,Ann Physik 5, 219 (1932); andC.A. Wert and R.M. Thomson,Physics of Solids, 2nd edition,McGraw-Hill Company, New York,1970.)

ELECTRICAL

Chapter 1-

• Space Shuttle Tiles: --Silica fiber insulation offers low heat conduction.

• Thermal Conductivity of Copper: --It decreases when you add zinc!

Composition (wt%Zinc)Ther

mal

Con

duct

ivity

(W

/m-K

)

400

300200

10000 10 20 30 40

5

Fig. 19.0, Callister 6e.(Courtesy of LockheedMissiles and SpaceCompany, Inc.)

100m

Adapted fromFig. 19.4W, Callister 6e. (Courtesy of Lockheed Aerospace Ceramics Systems, Sunnyvale, CA)(Note: "W" denotes fig. is on CD-ROM.)

Adapted from Fig. 19.4, Callister 6e.(Fig. 19.4 is adapted from Metals Handbook: Properties and Selection: Nonferrous alloys and Pure Metals, Vol. 2, 9th ed., H. Baker, (Managing Editor), American Society for Metals, 1979, p. 315.)

THERMAL

Chapter 1-

• Magnetic Permeability vs. Composition: --Adding 3 atomic % Si makes Fe a better recording medium!

Magnetic FieldMag

netiz

atio

n

Fe+3%SiFe

Adapted from C.R. Barrett, W.D. Nix, andA.S. Tetelman, The Principles ofEngineering Materials, Fig. 1-7(a), p. 9,1973.Electronically reproducedby permission of Pearson Education, Inc.,Upper Saddle River, New Jersey.

Fig. 20.18, Callister 6e., (Fig. 20.18 is from J.U. Lemke, MRS Bulletin, Vol. XV, No. 3, p. 31, 1990.)

• Magnetic Storage: --Recording medium is magnetized by recording head.

MAGNETIC

Chapter 1-

• Transmittance: --Aluminum oxide may be transparent, translucent, or opaque depending on the material structure.

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Adapted from Fig. 1.2,Callister 6e.(Specimen preparation,P.A. Lessing; photo by J. Telford.)

single crystalpolycrystal:low porosity

polycrystal:high porosity

OPTICAL

Chapter 1-

• Stress & Saltwater... --causes cracks!

• Heat treatment: slows crack speed in salt water!

4m

--material: 7150-T651 Al "alloy" (Zn,Cu,Mg,Zr)

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.)

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Adapted from Fig. 17.0, Callister 6e.(Fig. 17.0 is from Marine Corrosion, Causes, and Prevention, John Wiley and Sons, Inc., 1975.)

Adapted from Fig. 11.24,Callister 6e. (Fig. 11.24 provided courtesy of G.H.Narayanan and A.G. Miller, Boeing CommercialAirplane Company.)

“held at 160C for 1hr before testing”

increasing loadcrac

k sp

eed

(m/s

)

“as-is”

10-10

10-8

Alloy 7178 tested in saturated aqueous NaCl solution at 23C

DETERIORATIVE

Chapter 1-

• Use the right material for the job.

• Understand the relation between properties, structure, and processing.

• Recognize new design opportunities offered by materials selection.

Course Goals:

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SUMMARY