FE_review_Introduction to materials engineering

FE_review_Introduction to materials engineering

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

2. 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?

3. Review: Chapter 1 – Introduction
•Types of Materials
–Metals
–Polymers
–Ceramics

4. 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

5. 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

6. 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
n
d
hk

7. 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

8. Review: Chapter 4 (cont.)
•Microscopy
–Optical
–Electron Microscopy
–Sample Prep – polishing & etching

9. Review: Chapter 5
•Diffusion
–Vacancy diffusion
–Interstitial diffusion
–Fick’s First Law
Second Law
–Temp effect
–Slab- non-steady state
dx
dC
DJ
2
2
x
C
D
t
C












RT
Q
expDD
d
0









Dt2
x
erf1
CC
CC
0s
0x

10. Review: Chapter 19
•Thermal Properties
–Heat Capacity
•C = dQ/dTC
p > C
v
–phonons
–thermal expansion coefficient
l/l = 
l T
–thermal conduction of heat
•q = -k (dT/dx)
–k = heat transfer coefficient

11. Review: Chapter 6
Mechanical Properties
•Stress vs. strain
•Hooke’s law E 


A
F
0

0
0




y
TS

F
E

12. Review: Chapter 6
•Poisson’s Ratio
•Toughness
•Resilience
•Hardness
z
x
z
y







13. Review – Chapter 7
Dislocations 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 (A
0
-A
f
)/A
0
•Recovery, recrystallization, & grain growth

14. 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

15. Review, Chapter 8 (cont.)
•Griffith Crack - Stress concentration
–Critical stress
•Fatigue – cyclic stress
•Creep
2
1
s
c
a
E2









0tm
K

16. 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

17. 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

18. Review- Chapter 9 (cont.)
•Eutectic L S
1+S
2
•Eutectoid S
1 S
2+S
3
•Peritectic S
1
+L S
2
•Hypoeutectoid
•Hypereutectoid
cool
heat
cool
heat
cool
heat

19. Review - Chapter 10
Rate of Phase Transformation
•Nucleation process

20. Review - Chapter 10 (cont)
•Phase transformations vs. temperature
and time
–Pearlite
–Martensite
–Bainite
–Spheroidite
Chapter 11
•Heat Treatments

21. Review – Chapter 11
Fabrication of Metals
•Forming
–Forging
–Rolling
–Extrusion
–Drawing
•Casting
•Powder metallurgy
•Welding
•Machining
•Alloy Nomenclature
•Cast Irons – addition of Si catalyzes graphite
formation
•Refractories

22. Review – Chapter 12
Ceramics
•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 SiO
4
4-
–layered
–countercations to neutralize charge

23. 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

24. 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

25. 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)

26. Chapter 14 – Polymers
•Molecular Weight
–Actually a molecular weight distribution
–M
n = Number-averaged molecular weight
–M
w
= Weight-averaged molecular weight
–Polydispersity = M
w
/M
n
•A measure of the width of the distribution
•Chain Shapes
–linear
–branched
–crosslinked
–network

27. Chapter 14 & 15 – Polymers
•Isomerism
–Isotactic
–Syndiotactic
–Atactic
–Cis vs. Trans
–Copolymers
•Random
•Alternating
•Block
•Crystallinity
–Spherulites

28. 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 E
c
(u) = E
m
V
m
+ E
p
V
p
–Lower limit

EVEV
EE
E
mppm
pm
c



29. Chapter 16 – Composites
•Reinforced concrete
•Prestressed concrete
•Fiber reinforced
–Short vs. long fibers
–Critical length
–allignment
c
f
c
2
d




30. Chapter 18 – Electrical Properties
Definitions
•R = resistance = Ohms
 = RA/l = resistivity = ohm meter
 = 1/ = conductivity
•C = Q/V = capacitance

r = /
o = dielectric constant

31. 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

32. Chapter 20 – Superconductivity
•T
c = temperature below which
superconducting
= critical temperature
J
c = critical current density if J > J
c not
superconducting
H
c = critical magnetic field if H > H
c not
superconducting
•Meissner Effect - Superconductors expel
magnetic fields

33. Chapter 21 – Optical Properties
•Electromagnetic radiation
•Angle of refraction at interface


hc
hE
)mediuminlightofvelocity(v
)vacuuminlightofvelocity(c
indexrefractiven 



sin
sin
n
n

34. 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
tyreflectivi
2n
1n
R
2









t
I
I
ln
0








35. Questions???
•Contact Prof. David Rethwisch to discuss
questions.
–office 4139 SC
–Phone [phone]
–email [email protected]