Review: FE Exam

• Text: “Materials Science and Engineering: An Introduction,” 6th ed., William D. Callister, Jr., Wiley, 2003.

Review: FE Exam

– Part 1 – atomic structure & bonding• What holds materials together?

– Part 2 – Imperfections in solids• How are they packed?

– Part 3 – mechanical properties• How do they deform?

Review: Chapter 1 – Introduction

• Types of Materials–Metals– Polymers– Ceramics

Review: Chapt 2-Atomic Structure

• Atomic Number, Atomic Weight, etc. • Periodic table– Electron Structure - valence electrons –

unfilled shells• Bonding– ionic– covalent–metallic– van der Waals

Review: Chapt 3 – Crystal Structures

• Unit Cell–Metals• BCC• FCC• HCP

• Atomic packing factor• Coordination number• Crystallographic directions [uvw] families of directions <uvw>• Linear density of atoms (ld) = atoms/unit

length

Review: Chapt 3 – Crystal Structures (cont.)

• Miller indices of planes (hkl)

families of planes {hkl}• Planar density (pd) = # of atoms/ unit area

(pd) = S.A. atoms/S.A. unit cell

• X-Ray Diffraction

– Bragg’s law

sin2

ndhk

Review: Chapter 4

• Imperfections– Point defects

• Interstitial• Vacancy• Substitution• Solid solutions

– Line defects• Edge dislocation - Burgers vector perpendicular to

dislocation line• Screw dislocation - Burgers vector parallel to

dislocation line

– Planar defects• Twin• Stacking fault• Grain Boundary

Review: Chapter 4 (cont.)

• Microscopy– Optical– Electron Microscopy– Sample Prep – polishing & etching

Review: Chapter 5

• Diffusion– Vacancy diffusion– Interstitial diffusion

– Fick’s First Law

Second Law

– Temp effect

– Slab- non-steady state

dx

dCDJ

2

2

x

CD

t

C

RT

QexpDD d

0

Dt2

xerf1

CC

CC

0s

0x

Review: Chapter 19

• Thermal Properties – Heat Capacity• C = dQ/dT Cp > Cv

– phonons– thermal expansion coefficient

l/l = l T

– thermal conduction of heat• q = -k (dT/dx)

– k = heat transfer coefficient

Review: Chapter 6Mechanical Properties

• Stress vs. strain

• Hooke’s law E

A

F

0

0

0

y

TS

F

E

Review: Chapter 6

• Poisson’s Ratio

• Toughness• Resilience• Hardness

z

x

z

y

Review – Chapter 7Dislocations and Strengthening Mechanisms• Deformation by motion of dislocations– Slip plane – plane of easiest deformation – Slip direction – direction of easiest slippage– Slip system – direction and plane

• Applied stress must be resolved along slip direction = cos cos

• Twinning• Mechanism of strengthening– Grain size reduction– Solid-solution hardening

• impurities reduce mobility of dislocations

– Strain hardening %CW = 100 x (A0-Af)/A0

• Recovery, recrystallization, & grain growth

Review – Chapter 8

Fracture – failure– Ductile fracture • Large deformations

– cone & cup– small necked regions

– Brittle fracture• Almost no deformation other than failure

– transgranular – within grain– intergranular- between grains

Review, Chapter 8 (cont.)

• Griffith Crack - Stress concentration

– Critical stress

• Fatigue – cyclic stress• Creep

2

1

sc a

E2

0tm K

Review- Chapter 9 Phase Diagrams• Isomorphous system– 1. How many &

which phases– 2. Use tie line to

read compositions– 3. Use lever rule

to get weight fractions

Review- Chapter 9• binary eutectic system

– 1. How many & which phases– 2. Use tie line to read compositions– 3. Use lever rule to get weight fractions

Review- Chapter 9 (cont.)

• Eutectic L S1+S2

• Eutectoid S1 S2+S3

• Peritectic S1+L S2

• Hypoeutectoid• Hypereutectoid

cool

heat

cool

heat

cool

heat

Review - Chapter 10

Rate of Phase Transformation• Nucleation process

Review - Chapter 10 (cont)• Phase transformations vs. temperature

and time– Pearlite–Martensite– Bainite– Spheroidite

Chapter 11• Heat Treatments

Review – Chapter 11Fabrication of Metals• Forming– Forging– Rolling– Extrusion– Drawing

• Casting• Powder metallurgy• Welding• Machining• Alloy Nomenclature• Cast Irons – addition of Si catalyzes graphite

formation• Refractories

Review – Chapter 12Ceramics• Crystal structures– oxygen larger – generally in FCC lattice– cations go in lattice sites based on

• size• stoichiometry• charge balance• bond hybridization

– no good slip planes – brittle failure• Silicates

– built up of SiO44-

– layered– countercations to neutralize charge

Chapter 12 – Ceramics

• Carbon forms– diamond– graphite– fullerenes– amorphous

• Lattice imperfections– Frenkel defect – cation displaced into

interstitial site– Schottky defect – missing cation/anion pair

• Phase diagrams• Mechanical properties

Chapter 13 – Ceramics (cont)• Glasses – amorphous sodium or borosilicates– Forming

• pressing• drawing• blowing

• Clay products - forming– Hydroplastic forming– Slip casting– Refractories– Powder pressing

• Cements• Advanced ceramics

Chapter 14 – Polymers

• Types of polymers– Commodity plastics

• PE = Polyethylene• PS = Polystyrene• PP = Polypropylene• PVC = Poly(vinyl chloride)• PET = Poly(ethylene terephthalate)

– Specialty or Engineering Plastics• Teflon (PTFE) = Poly(tetrafluoroethylene)• PC = Polycarbonate (Lexan)• Polysulfones• Polyesters and Polyamides (Nylon)

Chapter 14 – Polymers

• Molecular Weight– Actually a molecular weight distribution

– Mn = Number-averaged molecular weight

– Mw = Weight-averaged molecular weight

– Polydispersity = Mw/Mn

• A measure of the width of the distribution

• Chain Shapes– linear– branched– crosslinked– network

Chapter 14 & 15 – Polymers

• Isomerism– Isotactic– Syndiotactic– Atactic– Cis vs. Trans– Copolymers

• Random• Alternating• Block

• Crystallinity– Spherulites

Chapter 16 – Composites

• Combine materials with objective of getting a more desirable combination of properties

• Dispersed phase• Matrix• Particle reinforced– large particle– dispersion strengthened

• Rule of mixtures

– Upper limit Ec(u) = EmVm + EpVp

– Lower limit

EVEV

EEE

mppm

pmc

Chapter 16 – Composites

• Reinforced concrete• Prestressed concrete• Fiber reinforced– Short vs. long fibers– Critical length

– allignmentc

fc 2

d

Chapter 18 – Electrical Properties

Definitions• R = resistance = Ohms = RA/l = resistivity = ohm meter = 1/ = conductivity• C = Q/V = capacitance r = /o = dielectric constant

Chapter 18 – Electrical Properties

• Energy Bands – valance vs. conduction– Conductor – no band gap– Insulator – wide gap– Semiconductor – narrow gap

• Intrinsic – pure or compound– Electron vs. hole (which carries charge)

• Extrinsic (doped)– n-type – donor levels – extra electrons

– p-type – acceptor levels – extra holes

• Microelectronics– pn junction – rectifier diode– npn transistor

Chapter 20 – Superconductivity

• Tc = temperature below which superconducting

= critical temperature

Jc = critical current density if J > Jc not superconducting

Hc = critical magnetic field if H > Hc not superconducting

• Meissner Effect - Superconductors expel magnetic fields

Chapter 21 – Optical Properties

• Electromagnetic radiation

• Angle of refraction at interface

hchE

)mediuminlightofvelocity(v

)vacuuminlightofvelocity(cindexrefractiven

sin

sin

n

n

Chapter 21 – Optical Properties

• Light interaction with solids– Reflection– Absorption– Scattering– Transmission

• Semiconductors – absorb light with energy greater than band gap

• Luminescence – emission of light by a material– phosphorescence = If very stable (long-lived = >10-8 s)– fluorescence = If less stable (<10-8 s)

• LASERS – coherent light• Fiber optics

tyreflectivi2n

1nR

2

tI

Iln

0

Questions???

• Contact Prof. David Rethwisch to discuss questions.– office 4139 SC– Phone 335-1413– email david-rethwisch@uiowa.edu