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 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

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

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  yy TS FF E

12. Review: Chapter 6 Poisson’s Ratio Toughness Resilience Hardness

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

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

29. Chapter 16 – Composites Reinforced concrete Prestressed concrete Fiber reinforced –Short vs. long fibers –Critical length –allignment

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

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

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