Chapter 1 basics
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This chapter introduces materials science and engineering. It discusses the relationships between structure, processing, and properties of materials. Structure is described at the subatomic, atomic, microscopic, and macroscopic scales. Key terminology for measuring small lengths is introduced. The chapter outlines how materials are classified and provides examples of metals, ceramics, polymers, semiconductors, and composites. It discusses how electrical, magnetic, optical, thermal, mechanical, and deterioration properties depend on composition, bonding, crystal structure, and microstructure. The chapter goals are to enable selection of the right material for an application and understand how structure and processing influence material properties and new design opportunities.
Chapter 1 basics
- 1. Introduction To Materials Science and Engineering, Ch. 1 Chapter 1 Materials for Engineering A fly-by during deployment of the aircraft carrier USS Stennis. The pilot was grounded for 30 days, but he likes the picture and thinks it was worth it. 1 University of Tennessee, Dept. of Materials Science and Engineering
- 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. 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. 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 = 1Å 1 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. 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 stripes Schematic, 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. Introduction To Materials Science and Engineering, Ch. 1 Processing Structure Properties Performance 6 University of Tennessee, Dept. of Materials Science and Engineering
- 7. Introduction To Materials Science and Engineering, Ch. 1 Structure, 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. Introduction To Materials Science and Engineering, Ch. 1 The Materials Selection Process 1. 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. Introduction To Materials Science and Engineering, Ch. 1 Composition, Bonding, Crystal Structure and Microstructure DEFINE Materials Properties Composition Bonding Crystal Structure Thermomechanical Processing Microstructure Electrical & Thermal Mechanical Optical Magnetic Properties Properties Properties Properties 9 University of Tennessee, Dept. of Materials Science and Engineering
- 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. 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. 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. 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. Introduction To Materials Science and Engineering, Ch. 1 Types of Materials Metals: 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. Introduction To Materials Science and Engineering, Ch. 1 Types of Materials Let 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 'electron sea' that "glues" the ions together. Strong, ductile, conduct electricity and heat well, are shiny if polished. Semiconductors: the bonding is covalent (electrons are shared between atoms). Their electrical properties depend strongly on minute proportions of contaminants. Examples: Si, Ge, GaAs. Ceramics: atoms behave like either positive or negative ions, and are bound by Coulomb forces. They are usually combinations of metals or semiconductors with oxygen, nitrogen or carbon (oxides, nitrides, and carbides). Hard, brittle, insulators. Examples: glass, porcelain. Polymers: are bound by covalent forces and also by weak van der Waals forces, and usually based on C and H. They decompose at moderate temperatures (100 – 400 C), and are lightweight. Examples: plastics rubber. 15 University of Tennessee, Dept. of Materials Science and Engineering
- 16. Introduction To Materials Science and Engineering, Ch. 1 Metals Several uses of steel and pressed aluminum. 16 University of Tennessee, Dept. of Materials Science and Engineering
- 17. Introduction To Materials Science and Engineering, Ch. 1 Ceramics Examples of ceramic materials ranging from household and lab products to high performance combustion engines which utilize both Metals and ceramics. 17 University of Tennessee, Dept. of Materials Science and Engineering
- 18. Introduction To Materials Science and Engineering, Ch. 1 Ceramics Crystalline ceramics (a) and non-crystalline glasses (b) yield inherently different properties for applications. Open circles represent nonmetallic atoms, solids represent metal atoms. 18 University of Tennessee, Dept. of Materials Science and Engineering
- 19. Introduction To Materials Science and Engineering, Ch. 1 Ceramics Examples of glasses. Depending on the material structure, the glass can be opaque, transparent, or translucent. Glasses can also be Processed to yield high thermal shock resistance. 19 University of Tennessee, Dept. of Materials Science and Engineering
- 20. Introduction To Materials Science and Engineering, Ch. 1 Polymers Polymers or commercially called “Plastics” need no intro. 20 University of Tennessee, Dept. of Materials Science and Engineering
- 21. Introduction To Materials Science and Engineering, Ch. 1 Polymers Polymer composite materials, reinforcing glass fibers in a polymer matrix. 21 University of Tennessee, Dept. of Materials Science and Engineering
- 22. Introduction To Materials Science and Engineering, Ch. 1 Semiconductors (a) (b) (a) Micro-Electrical-Mechanical Systems (MEMS), (b) Si wafer for computer chip devices. 22 University of Tennessee, Dept. of Materials Science and Engineering
- 23. Introduction To Materials Science and Engineering, Ch. 1 23 University of Tennessee, Dept. of Materials Science and Engineering
- 24. Introduction To Materials Science and Engineering, Ch. 1 Course 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