Chapter 1 basics

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Chapter 1 basics

  1. 1. Introduction To Materials Science and Engineering, Ch. 1 Chapter 1 Materials for EngineeringA fly-by during deployment of the aircraft carrier USSStennis. The pilot was grounded for 30 days, but helikes the picture and thinks it was worth it. 1 University of Tennessee, Dept. of Materials Science and Engineering
  2. 2. Introduction To Materials Science and Engineering, Ch. 1 Materials Science and Engineering• Materials Science – Investigating relationships that exist between the structure and properties of materials• Materials Engineering – Is, on the basis of these structure-property correlations, designing or engineering the structure of a material to produce a pre-determined set of properties 2 University of Tennessee, Dept. of Materials Science and Engineering
  3. 3. Introduction To Materials Science and Engineering, Ch. 1 Structure• Sub atomic – electrons and nuclei (protons and neutrons)• Atomic – organization of atoms or molecules• Microscopic – groups of atoms that are normally agglomerated together• Macroscopic – viewable with the un-aided eye 3 University of Tennessee, Dept. of Materials Science and Engineering
  4. 4. Introduction To Materials Science and Engineering, Ch. 1 Terminology mil = 1 / 1000 inch = 25.4 µm micrometer = 1 / 1,000,000 meter = 1µm Angstrom = 1 / 10,000,000,000 meter = 1Å1 MICROMETER IS TWO WAVELENGTHS OF GREEN LIGHT LONG A 1 MICRON WIDE LINE ON A CD IS THE SAME SCALE AS A 100 FOOT WIDE ROAD ON NORTH AMERICA A HAIR IS 100 MICROMETERS 4 University of Tennessee, Dept. of Materials Science and Engineering
  5. 5. Introduction To Materials Science and Engineering, Ch. 1 THE SCALE OF THINGS The 21st century challenge -- Fashion materials at the nanoscale with desired properties and functionality Things Natural 100 m 1 meter (m) Things Manmade 10-1 m 0.1 m 100 mm Objects fashioned from Progress in miniaturization metals, ceramics, glasses, polymers ... Monarch butterfly ~ 0.1 m 0.01 m Dust mite 10-2 m 300 µm 1 cm Head of a pin 10 mm 1-2 mm Cat ~ 0.3 m 10-3 m 1 millimeter (mm) Human hair Microelectronics ~ 50 µm wide 0.1 mm Fly ash 10-4 m MEMS (MicroElectroMechanical Systems) Devices Bee ~ 10-20 µm 100 µm 10 -100 µm wide Microworld Progress in atomic-level understanding ~ 15 mm The 10-5 m 0.01 mm 10 µm 10-6 m 1 micrometer (µm) spectrum Visible Red blood cells with white cell Atoms of silicon Magnetic ~ 2-5 µm Red blood cells domains garnet spacing ~tenths of nm Pollen grain film 10-7 m 0.1 µm 11 µm wide 100 nm Nanoworld stripesSchematic, central core ATP synthase The 10-8 m 0.01 µm 10 nm Quantum dot array -- Indium arsenide germanium dots on silicon quantum dot 10-9 m 1 nanometer (nm) 10 nm DNA ~2 nm wide Cell membrane -10 5 University of Tennessee, Dept.10 m 0.1 nm of Materials Science and Engineering
  6. 6. Introduction To Materials Science and Engineering, Ch. 1Processing Structure Properties Performance 6 University of Tennessee, Dept. of Materials Science and Engineering
  7. 7. Introduction To Materials Science and Engineering, Ch. 1Structure, Processing, & Properties• Properties depend on structure ex: hardness vs structure of steel (d) 600 Hardness (BHN) 30µm 500 (c) Data obtained from Figs. 10.21(a) 400 (b) and 10.23 with 4wt%C composition, (a) and from Fig. 11.13 and associated 4µm discussion, Callister 6e. 300 Micrographs adapted from (a) Fig. 10.10; (b) Fig. 9.27;(c) Fig. 10.24; 30µm and (d) Fig. 10.12, Callister 6e. 200 30µm 100 0.01 0.1 1 10 100 1000 Cooling Rate (C/s)• Processing can change structure ex: structure vs cooling rate of steel 7 University of Tennessee, Dept. of Materials Science and Engineering
  8. 8. Introduction To Materials Science and Engineering, Ch. 1 The Materials Selection Process1. Pick Application Determine required Properties Properties: mechanical, electrical, thermal, magnetic, optical, deteriorative.2. Properties Identify candidate Material(s) Material: structure, composition.3. Material Identify required Processing Processing: changes structure and overall shape ex: casting, sintering, vapor deposition, doping forming, joining, annealing. 8 University of Tennessee, Dept. of Materials Science and Engineering
  9. 9. Introduction To Materials Science and Engineering, Ch. 1 Composition, Bonding, Crystal Structureand Microstructure DEFINE Materials Properties Composition Bonding Crystal Structure Thermomechanical Processing Microstructure Electrical & ThermalMechanical Optical Magnetic PropertiesProperties Properties Properties 9 University of Tennessee, Dept. of Materials Science and Engineering
  10. 10. Introduction To Materials Science and Engineering, Ch. 1 ELECTRICAL• Electrical Resistivity of Copper: 6 i Adapted from Fig. 18.8, Callister 6e. a t%N (Fig. 18.8 adapted from: J.O. Linde, 5 3 .32 Ann Physik 5, 219 (1932); and + Resistivity, ρ C.A. Wert and R.M. Thomson, Cu %N i (10-8 Ohm-m) Physics of Solids, 2nd edition, at i 4 2 .16 a t% N McGraw-Hill Company, New York, u+ .12 1970.) C 1 3 C u+ ed d eform a t%N i 2 1.12 Cu+ u 1 r e” C “Pu 0 -200 -100 0 T (°C)• Adding “impurity” atoms to Cu increases resistivity.• Deforming Cu increases resistivity. 10 University of Tennessee, Dept. of Materials Science and Engineering
  11. 11. Introduction To Materials Science and Engineering, Ch. 1 MAGNETIC• Magnetic Storage: • Magnetic Permeability --Recording medium vs. Composition: is magnetized by --Adding 3 atomic % Si recording head. makes Fe a better recording medium! Magnetization Fe+3%Si Fe Magnetic Field Adapted from C.R. Barrett, W.D. Nix, and Fig. 20.18, Callister 6e. A.S. Tetelman, The Principles of (Fig. 20.18 is from J.U. Lemke, MRS Bulletin, Engineering Materials, Fig. 1-7(a), p. 9, Vol. XV, No. 3, p. 31, 1990.) 1973. Electronically reproduced by permission of Pearson Education, Inc., Upper Saddle River, New Jersey. 11 University of Tennessee, Dept. of Materials Science and Engineering
  12. 12. Introduction To Materials Science and Engineering, Ch. 1 OPTICAL• Transmittance: --Aluminum oxide may be transparent, translucent, or opaque depending on the material structure. polycrystal: polycrystal:single crystal low porosity high porosity Adapted from Fig. 1.2, Callister 6e. (Specimen preparation, P.A. Lessing; photo by J. Telford.) 12 University of Tennessee, Dept. of Materials Science and Engineering
  13. 13. Introduction To Materials Science and Engineering, Ch. 1 DETERIORATIVE• Stress & Saltwater... • Heat treatment: slows --causes cracks! crack speed in salt water! crack speed (m/s) 10 -8 “as-is” “held at 160C for 1hr before testing” 10 -10 Alloy 7178 tested in saturated aqueous NaCl solution at 23C increasing load Adapted from Fig. 11.20(b), R.W. Hertzberg, "Deformation and Fracture Mechanics of Engineering Materials" (4th ed.), p. 505, Adapted from Fig. 17.0, Callister 6e. John Wiley and Sons, 1996. (Original source: Markus O. (Fig. 17.0 is from Marine Corrosion, Causes, Speidel, Brown Boveri Co.) and Prevention, John Wiley and Sons, Inc., 4µm 1975.) --material: 7150-T651 Al "alloy" (Zn,Cu,Mg,Zr) Adapted from Fig. 11.24, Callister 6e. (Fig. 11.24 provided courtesy of G.H. Narayanan and A.G. Miller, Boeing Commercial Airplane Company.) 13 University of Tennessee, Dept. of Materials Science and Engineering
  14. 14. Introduction To Materials Science and Engineering, Ch. 1 Types of MaterialsMetals: strong, ductile, tough, high density, conductors.Ceramics: strong, brittle, low density, insulators.Polymers: weak, ductile, low density, insulators.Semiconductors: weak, brittle, low density, semi-conductors.Composites: strong, ductile, low density, conductors, insulators.Crystals: atoms have long range periodic order (a).Glasses: atoms have short range order only (b). (a) (b) 14 University of Tennessee, Dept. of Materials Science and Engineering
  15. 15. Introduction To Materials Science and Engineering, Ch. 1 Types of MaterialsLet us classify materials according to the way the atoms are bound together(Chapter 2).Metals: valence electrons are detached from atoms, and spread in an electronsea that "glues" the ions together. Strong, ductile, conduct electricity and heatwell, are shiny if polished.Semiconductors: the bonding is covalent (electrons are shared betweenatoms). Their electrical properties depend strongly on minute proportions ofcontaminants. Examples: Si, Ge, GaAs.Ceramics: atoms behave like either positive or negative ions, and are boundby Coulomb forces. They are usually combinations of metals orsemiconductors with oxygen, nitrogen or carbon (oxides, nitrides, andcarbides). Hard, brittle, insulators. Examples: glass, porcelain.Polymers: are bound by covalent forces and also by weak van der Waalsforces, and usually based on C and H. They decompose at moderatetemperatures (100 – 400 C), and are lightweight. Examples: plastics rubber. 15 University of Tennessee, Dept. of Materials Science and Engineering
  16. 16. Introduction To Materials Science and Engineering, Ch. 1 MetalsSeveral uses of steel and pressed aluminum. 16University of Tennessee, Dept. of Materials Science and Engineering
  17. 17. Introduction To Materials Science and Engineering, Ch. 1 CeramicsExamples of ceramic materials ranging from household and labproducts to high performance combustion engines which utilize bothMetals and ceramics. 17 University of Tennessee, Dept. of Materials Science and Engineering
  18. 18. Introduction To Materials Science and Engineering, Ch. 1 CeramicsCrystalline ceramics (a) and non-crystalline glasses (b) yieldinherently different properties for applications. Open circlesrepresent nonmetallic atoms, solids represent metal atoms. 18 University of Tennessee, Dept. of Materials Science and Engineering
  19. 19. Introduction To Materials Science and Engineering, Ch. 1 CeramicsExamples of glasses. Depending on the material structure, the glasscan be opaque, transparent, or translucent. Glasses can also beProcessed to yield high thermal shock resistance. 19 University of Tennessee, Dept. of Materials Science and Engineering
  20. 20. Introduction To Materials Science and Engineering, Ch. 1 PolymersPolymers or commercially called “Plastics” need no intro. 20 University of Tennessee, Dept. of Materials Science and Engineering
  21. 21. Introduction To Materials Science and Engineering, Ch. 1 PolymersPolymer composite materials, reinforcing glass fibers in apolymer matrix. 21 University of Tennessee, Dept. of Materials Science and Engineering
  22. 22. Introduction To Materials Science and Engineering, Ch. 1 Semiconductors (a) (b)(a) Micro-Electrical-Mechanical Systems (MEMS), (b) Si waferfor computer chip devices. 22 University of Tennessee, Dept. of Materials Science and Engineering
  23. 23. Introduction To Materials Science and Engineering, Ch. 1 23University of Tennessee, Dept. of Materials Science and Engineering
  24. 24. Introduction To Materials Science and Engineering, Ch. 1Course Goals: SUMMARY • Use the right material for the job. • Understand the relation between properties, structure, and processing. • Recognize new design opportunities offered by materials selection. 24 University of Tennessee, Dept. of Materials Science and Engineering

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