Review: FE Exam Text: “Materials Science and Engineering: An Introduction,” 6 th ed., William D....
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Transcript of Review: FE Exam Text: “Materials Science and Engineering: An Introduction,” 6 th ed., William D....
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 [email protected]