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EMT282 Principles of Engineering Materials

This course provides an introduction to the fundamental concepts of materials structure and properties, covering topics such as atom and bonding, material structure, solidification, mechanical, electrical and optical properties, and more.

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EMT282 Principles of Engineering Materials

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  1. EMT282 Principles of Engineering Materials Dr. Rozana Aina Maulat Osman Microelectronic Engineering Block 9: Room 00-01-0A 04-9885532 Lecture 1: Introduction

  2. Grading policies • Course work: 30% PBL Report = 10% PBL Presentation = 5% Assignment/Quizzes = 15% • Examination: 70% Mid Term Examination = 10% End Term Examination = 10% Final Examination = 50%

  3. Course Outcome • CO1: • Ability to apply and understand the fundamental concept of materials structure and properties. • CO2: • Ability to evaluate,analyse andcompare various material characteristic and properties. • CO3: • Ability to act and function effectively as individual, and as a member or leader in diverse teams and in multidisciplinary settings to solve material reliability.

  4. Syllabus • Introduction to Material Properties • Atom and Bonding • Material Structure and Atomic Packing • Solidification and Crystal Imperfection • Diffusion and Phase Diagram • Mechanical Properties of Material • Electrical and Optical Properties • Material Oxidation, Corrosion

  5. References • Anthony R. West, (2014).Solid State Chemistry and its Applications, 2nd Edition, Student Edition, Wiley. • William D. Callister Jr. and David G. Rethwisch (2013).Materials Science and Engineering: An Introduction,9thEdition,Wiley • William Smith and JavadHashemi, (2011). Foundations of Materials Science and Engineering, 5th Edition, McGrawhill. • Donald R. Askeland,Pradeep P. Fulay and Wendelin J. Wright (2010).The Science and Engineering of Materials, 6thEdition,Cengage Learning. • Michael F. Ashby, Hugh Shercliff and David Cebon (2007). Materials: engineering, science, processing, and design, Butterworth-Heinemann.

  6. Content • 1. Introduction • 2. Type of materials • 3. Materials properties • 4. Advanced materials

  7. Engineering materials Materials science • Investigate relationship between structure and properties materials Materials engineering • Designing or engineering the structure to produce predetermined set of properties

  8. Materials • Types of materials • Metals • Polymers • Ceramics • composite • Properties of materials • Mechanical • Electrical • Magnetic • Thermal • Chemical stability

  9. The development of material over time The evolution of engineering materials with time. Note the highly nonlinear scale. (From M. F. Ashby, Materials Selection in Mechanical Design, 2nd ed., Butterworth-Heinemann, Oxford, 1999.)

  10. Metals • Composed of one or more metallic elements (Iron, Copper, Aluminum) • Metallic element may combine with nonmetallic elements (carbon, nitrogen, oxygen) in relatively small amount. Mechanical Properties: • Stiff & strong • Ductile (large amount of deformation without fracture) • Resistant to fracture. • Metallic materials have large numbers of nonlocalized electron. • Good conductors of electricity & heat • Not transparent

  11. Example: The Golden Gate Bridge north of San Francisco, California, is one of the most famous and most beautiful examples of a steel bridge. (Courtesy of Dr. Michael Meier.)

  12. Polymers • Consist of organic (carbon-containing) long molecular chains or network • Plastic & rubber materials (Poly vinyl Chloride (PVC), Polyester) • Organic compound – carbon, hydrogen & other nonmetallic elements (O, N, Si) Mechanical Properties: • Stiffness & strength per mass are comparable to metal&ceramic • Ductile & pliable (easily formed into complex shape) • Inert chemically & unreactive in large number of environment • Tendency to soften and/or decomposed at modest temperature • Low electrical conductivity & nonmagnetic

  13. Example: Since its development during World War II, nylon fabric remains the most popular material of choice for parachute designs. (Courtesy of Stringer/Agence France Presse/Getty Images.)

  14. Ceramics • Compounds between metallic and nonmetallic elements. They are most frequently oxides, nitrides and carbides • Example: aluminum oxide, silicon dioxide, silicon nitride • Traditional ceramics: clay minerals, cement, glass Mechanical Properties: • Stiff & strong • Very hard • Brittle (lack ductility) • Highly susceptible to fracture. • Insulative to passage of heat & harsh environment • Optical characteristic – transparent, translucent, opaque • Oxide ceramic – exhibit magnetic behaviour

  15. Example: High-temperature sodium vapor lamp made possible by use of a translucent Al2O3 cylinder for containing the sodium vapor. (Note that the Al2O3cylinder is inside the exterior glass envelope.) (Courtesy of General Electric Company.)

  16. Composites • Compose of two (or more) individual materials Eg: (metal, ceramic, polymer) • Design goal: to achieve a combination of properties that is not display by any single material & also to incorporate the best characteristic of each of the component. • Example: fiberglass – small glass fiber embedded within polymeric material (epoxy/polyester) • Mechanical properties of glass fiber: strong, stiff, brittle • Mechanical properties of polymer: ductile, weak, flexible • Mechanical properties of fiberglass: strong, stiff, flexible, ductile, low density

  17. Example: Overview of the wide variety of composite parts used in the Air Force’s C- 17 transport (From Advance Composites, May/June 1988, p.53.)

  18. Advanced Materials • Electronic Materials • Semiconductor • Superconductor • Smart / Future Materials • Ferroelectric • Piezoelectric • Pyroelectric • Shape memory alloy • Bio-degradable • Nanomaterials • Smaller than 100nm

  19. Electronic Semiconductor • The bonding is covalent (electrons are shared between atoms). The electrical properties depend strongly on minute proportions of contaminants. • Silicon, Si • Germanium, Ge • Gallium Arsenide, GaAs • Gallium Nitride, GaN • Silicon Carbide, SiC • Silicon is an important electronic material that has triggered computer development revolution. Over the years, integrated circuits have been made with a greater density of transistors located on a single silicon chip with a corresponding decrease in transistor width. These chips play a vital role in computerized manufacturing.

  20. Electronic Materials • Not a major type of material, but are extremely important for advanced engineering technology: communication satellites, advanced computers, digital watches, robots, etc. • Silicon is the most important electronic material, it is modified in various ways to change its electrical properties.

  21. ii. Superconductor Superconductivity is a phenomenon of exactly zero electrical resistance • Superconducting magnets • MRI/NMR machines, mass spectrometers, and the beam-steering magnets used in particle accelerators

  22. Superconductor • High Curie Temperature, Tc , oxide ceramic superconductors –BSCCO (bisko) – Bismuth Strontium Calcium Copper Oxide: good, functionally; bad, structurally (brittle) ● Image courtesy: wiki

  23. Future Trends Materials • SmartMaterials : Change their properties by sensing external stimulus. • Ferroelectric : Ferroelectricity is a property of certain materials that have a spontaneouselectric polarization that can be reversed by the application of an external electric field. • Used as Ferroelectric Random Access Memory (FRAM) • Capacitor / Multilayer Ceramic Capacitor. • Piezoelectric materials: Produce electric field when exposed to force and vice versa. • Used in actuators and vibration reducers. • piezoelectric sensor • piezoelectric ultrasound – known as piezosurgery

  24. Future Trends Materials • SmartMaterials : Change their properties by sensing external stimulus. • Pyroelectric : Produce electric field when exposed to heat or cool and vice versa. • pyroelectric sensor • passive infrared sensor

  25. Future Trends Materials • Future Materials • Shape memory alloys: Strained material reverts back to its original shape above a critical temperature. • Used in heart valves and to expand arteries. • Bio-degradable materials: return to compounds found in nature. Degradation caused by enzymatic process resulting from the action of cells • Example:bio-plastic • Biodegradable electronics • Biodegradable polythene film

  26. Con..Biodegradable Materials

  27. Future Trends Materials • MEMS: Microelectromechanical systems. • Miniature devices • Micro-pumps, sensors • Nanomaterials:Characteristic length < 100 nm • Examples: ceramics powder and grain size < 100 nm • Nanomaterials are harder and stronger than bulk materials. • Have biocompatible characteristics ( as in Zirconia) • Transistors and diodes are developed on a nanowire.

  28. Classification and application of material’s engineering

  29. Variety in materials Image courtesy: Caltech Engineering Design lab handout

  30. PROPERTIESCOMPARISON

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