1. Chapter 1- Introduction to Materials Science & Engineering Lesson Objective... Introduce fundamental concepts in MSE You will learn about: material structure how structure dictates properties how processing can change structure This course will help you to: use materials properly realize new design opportunities with materials a

2. Chapter 1- Engineered structures are not blackboxes. They are made from raw materials which have a processed internal structure. This internal structure affects the material and The engineered structure properties... Structure Properties Processing Structure ProcessingProperties

3. Chapter 1- Structural featureDimension (m) atomic bonding missing/extra atoms crystals (ordered atoms) and crystal defects second phase particles crystal texturing < 10 -10 10 -10 10 -8 -10 10 -8 -10 -4 > 10 -6 1 Structure has many dimensions…

4. Chapter 1- Understanding Size How big (small) are we talking about? Classical systems are macroscopic and nanosystems are nanoscopic.

5. Chapter 1- Understanding Size 1 meter source: Glenn Fishbine - CERN http://microcosm.web.cern.ch/microcosm

6. Chapter 1- Understanding Size 10 centimeters source: Glenn Fishbine - CERN http://microcosm.web.cern.ch/microcosm

7. Chapter 1- Understanding Size 1 centimeter source: CERN http://microcosm.web.cern.ch/microcosm

8. Chapter 1- Understanding Size 100-1000 micrometers source: CERN http://microcosm.web.cern.ch/microcosm

9. Chapter 1- Understanding Size 10 micrometers source: CERN http://microcosm.web.cern.ch/microcosm

10. Chapter 1- Understanding Size 1 micrometer source: CERN http://microcosm.web.cern.ch/microcosm

11. Chapter 1- Understanding Size 100 nanometers source: CERN http://microcosm.web.cern.ch/microcosm

12. Chapter 1- Understanding Size 10 nanometers source: CERN http://microcosm.web.cern.ch/microcosm

13. Chapter 1- Understanding Size 1 nanometer source: CERN http://microcosm.web.cern.ch/microcosm

14. Chapter 1- Size Matters It’s not just how big you are It’s what you can do with it

15. Chapter 1- Understanding Effects Physical processes do not scale uniformly –gravity –friction –combustion –electrostatic –van der Walls –brownian –quantum

16. Chapter 1- Understanding Effects Gravity

17. Chapter 1- Understanding Effects Friction

18. Chapter 1- Understanding Effects Combustion

19. Chapter 1- Understanding Effects Electrostatic

20. Chapter 1- Understanding Effects van der Waals

21. Chapter 1- Understanding Effects brownian

22. Chapter 1- Understanding Effects Quantum "I don't like it, and I'm sorry I ever had anything to do with it.” - Erwin Schrodinger "I think that I can safely say that nobody understands quantum mechanics.” - Richard Feynman

23. Chapter 1- Understanding Size of Effects Centimeter: Gravity, friction, combustion, Newtonian mechanics Millimeter: Gravity, friction, combustion, electrostatic, magnetic Micrometer: Electrostatic, magnetic, van der Walls, Brownian Nanometer: Electrostatic, magnetic, van der Walls, Brownian, Quantum Angstrom: Quantum mechanics (1/10,000,000,000 meter)

24. Chapter 1- ex: hardness vs structure of steel Properties depend on structure Data obtained from Figs. 10.21(a) and 10.23 with 4wt%C composition, and from Fig. 11.13 and associated discussion, Callister 6e. Micrographs adapted from (a) Fig. 10.10; (b) Fig. 9.27;(c) Fig. 10.24; and (d) Fig. 10.12, Callister 6e. ex: structure vs cooling rate of steel Processing can change structure 2 Structure, Processing, & Property Hardness (BHN)

25. Chapter 1- 1. Pick ApplicationDetermine required Properties 2. Properties Identify candidate Material(s) 3. Material Identify required Processing Processing: changes structure and overall shape ex: casting, sintering, vapor deposition, doping forming, joining, annealing. Properties: mechanical, electrical, thermal, magnetic, optical, environment tolerance – corrosion resistance. Material: structure, composition. 3 The Materials Selection Process

26. Chapter 1- Electrical Resistivity of Copper: Adding “impurity” atoms to Cu increases resistivity. Deforming Cu increases resistivity. 4 Adapted from Fig. 18.8, Callister 6e. (Fig. 18.8 adapted from: J.O. Linde, Ann Physik 5, 219 (1932); and C.A. Wert and R.M. Thomson, Physics of Solids, 2nd edition, McGraw-Hill Company, New York, 1970.) ELECTRICAL

27. Chapter 1- Space Shuttle Tiles: --Silica fiber insulation offers low heat conduction. Thermal Conductivity of Copper: --It decreases when you add zinc! 5 Fig. 19.0, Callister 6e. (Courtesy of Lockheed Missiles and Space Company, Inc.) Adapted from Fig. 19.4W, Callister 6e. (Courtesy of Lockheed Aerospace Ceramics Systems, Sunnyvale, CA) (Note: "W" denotes fig. is on CD-ROM.) Adapted from Fig. 19.4, Callister 6e. (Fig. 19.4 is adapted from Metals Handbook: Properties and Selection: Nonferrous alloys and Pure Metals, Vol. 2, 9th ed., H. Baker, (Managing Editor), American Society for Metals, 1979, p. 315.) THERMAL

28. Chapter 1- Magnetic Permeability vs. Composition: --Adding 3 atomic % Si makes Fe a better recording medium! Adapted from C.R. Barrett, W.D. Nix, and A.S. Tetelman, The Principles of Engineering Materials, Fig. 1-7(a), p. 9, 1973.Electronically reproduced by permission of Pearson Education, Inc., Upper Saddle River, New Jersey. 6 Fig. 20.18, Callister 6e. (Fig. 20.18 is from J.U. Lemke, MRS Bulletin, Vol. XV, No. 3, p. 31, 1990.) Magnetic Storage: --Recording medium is magnetized by recording head. MAGNETIC

29. Chapter 1- Transmittance: --Aluminum oxide may be transparent, translucent, or opaque depending on the material structure. 7 Adapted from Fig. 1.2, Callister 6e. (Specimen preparation, P.A. Lessing; photo by J. Telford.) single crystal polycrystal: low porosity polycrystal: high porosity OPTICAL

30. Chapter 1- Stress & Saltwater... --causes cracks! Heat treatment: slows crack speed in salt water! 4m4m --material: 7150-T651 Al "alloy" (Zn,Cu,Mg,Zr) Adapted from Fig. 11.20(b), R.W. Hertzberg, "Deformation and Fracture Mechanics of Engineering Materials" (4th ed.), p. 505, John Wiley and Sons, 1996. (Original source: Markus O. Speidel, Brown Boveri Co.) 8 Adapted from Fig. 17.0, Callister 6e. (Fig. 17.0 is from Marine Corrosion, Causes, and Prevention, John Wiley and Sons, Inc., 1975.) Adapted from Fig. 11.24, Callister 6e. (Fig. 11.24 provided courtesy of G.H. Narayanan and A.G. Miller, Boeing Commercial Airplane Company.) Enviromental Tolerance

31. Chapter 1- Review: Mechanical Properties Stress vs. strain Hooke’s law  E  yy TS FF E

32. Chapter 1- Tensile stress

33. Chapter 1- Shear stress

34. Chapter 1- Shear deformation

35. Chapter 1- 35 Stress and Strain Stress: Force per unit area arising from applied load. Tension, compression, shear, torsion or any combination. Stress = σ = force/area Strain: ε – physical deformation response of a material to stress, e.g., elongation.

36. Chapter 1- 36 Simple tension: cable Simple shear: drive shaft Note:  = M/A c R here. Ski lift (photo courtesy P.M. Anderson) Common States of Stress

37. Chapter 1- 37 Simple compression: Note: compressive structural member (σ < 0). (photo courtesy P.M. Anderson) Common States of Stress

38. Chapter 1- 38 Elastic Deformation Elastic means reversible! F  Linear- elastic Non-Linear- elastic 2. Small load F  bonds stretch 1. Initial3. Unload return to initial

39. Chapter 1- 39 Plastic Deformation of Metals Plastic means permanent! 1. Initial2. Small load3. Unload planes still sheared F δ elastic + plastic bonds stretch & planes shear δ plastic ε elastic F  linear elastic linear elastic δ plastic

40. Chapter 1- 40 Tensile specimen Other types: -compression: brittle materials (e.g., concrete) -torsion: cylindrical tubes, shafts. Tensile test machine Strain Testing Often 12.8 mm x 60 mm specimen extensometer Adapted from Fig. 7.2, Callister & Rethwisch 3e. gauge length

41. Chapter 1- Use the right material for the job. Understand the relation between structure, properties, and processing. Recognize new design opportunities offered by materials selection. Lesson Goals: 9 SUMMARY