Review: FE Exam

1. Review: FE Exam • Text: “Materials Science and Engineering: An Introduction,” 6th 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

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/dT Cp > Cv • phonons • thermal expansion coefficient • l/l = l T • thermal conduction of heat • q = -k (dT/dx) • k = heat transfer coefficient

11. Review: Chapter 6Mechanical Properties • Stress vs. strain • Hooke’s law s = E e TS y 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 (A0-Af)/A0 • 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. cool cool cool heat heat heat Review- Chapter 9 (cont.) • Eutectic L S1+S2 • Eutectoid S1 S2+S3 • Peritectic S1+L S2 • Hypoeutectoid • Hypereutectoid

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 SiO44- • 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 • 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

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 Ec(u) = EmVm + EpVp • 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 • 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

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