Lecture One Introduction to Engineering Materials

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Lecture OneIntroduction to Engineering
Materials Applications
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Introduction to Engineering Materials
Applications

• Materials science is primarily concerned with the
  search for basic knowledge about the internal
  structure, properties, and processing of
  materials. Materials' engineering is mainly
  concerned with the use of fundamentals and
  applied knowledge of materials so that the
  materials can be converted into products
  necessary or desired by the society.
• Materials in Industry Industrial applications of
  materials science include materials design, cost,
  processing techniques (casting, rolling, welding,
  ion implantation, crystal growth, thin-film
  deposition, sintering, etc.) and analytical
  techniques (electron microscopy, x-ray
  diffraction, calorimetry, backscattering, neutron
  diffraction, etc.).

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General Categories of Engineering Materials Used
Today in Manufacturing Industries
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Materials Science Engineering
Materials Engineering Designing the structure to
achieve specific properties of materials.

• Processing
• Structure
• Properties
• Performance

Materials Science Investigating the relationship
between structure and properties of materials.
Processing gtgt Structure gtgt Properties gtgt
Performance
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General Categories of Engineering Materials Used
Today in Manufacturing Industries
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What is Materials Science and Engineering?

• Materials Performance Strength-to-weight ratio,
  formability, cost
• Processing gtgtgt Structure gtgtgt Properties gtgtgt
  Performance
• Composition means the chemical make-up of a
  material.
• Structure means a description of the
  arrangements of atoms or ions in a material.
• Synthesis is the process by which materials are
  made from naturally occurring or other chemicals.
• Processing means different ways for shaping
  materials into useful components or changing
  their properties.

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What is Materials Science Engineering?

• Materials Processing
• Casting
• Forging
• Extrusion
• Stamping
• Nanotechnology
• Sintering

• Materials Characterization
• Diffraction with x-rays, electrons, or neutrons
  and various forms of spectroscopy and chemical
  analysis
• Energy-dispersive spectroscopy (EDS),
• Chromatography,
• Thermogravimetric analysis,
• Electron microscope analysis

• Materials Properties
• Physical behavior, Response to environment
• Mechanical (e.g., stress-strain)
• Thermal
• Electrical
• Magnetic
• Optical
• Corrosive

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Subfields of Materials Science
Introduction to Engineering Materials
Applications

• Biomaterials Metals for implantation must be
  corrosion resistant. Three main categories of
  metals for implants are stainless steels,
  cobalt-chromium alloys and titanium alloys.
  Additional metals used for dental implants are
  amalgam and gold.
• Electronic Materials Semiconductors used to
  create integrated circuits, storage media,
  sensors, and other devices. Semiconductors have
  special electronic properties which allow them to
  be insulating or conducting depending on their
  composition. Examples (Silicon and Germanium,
  III-V Compounds e.g. GaAs)
• Main application of semiconductors are
  transistors, light emitting diodes (LEDs) and
  diode lasers). Semiconductors are used in
  computers (45), consumer products (23),
  communications equipment (13), manufacturing
  industries (12), automobiles (5), and by the
  military (2).

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Subfields of Materials Science
Introduction to Engineering Materials
Applications

• Piezoelectric Materials Piezoelectric materials
  are used in acoustic transducers, which convert
  acoustic (sound) waves into electric fields, and
  electric fields into acoustic waves. Transducers
  are found in telephones, stereo music systems,
  and musical instruments. Quartz, a piezoelectric
  material, is often found in clocks and watches.
• Magnetic Materials Magnetic materials are used
  in electrical power applications such as
  transformers and motors, in video monitor picture
  tubes to move electron beams, and in computer
  disks or video or audio tapes to record
  information. Most materials can be classified as
  diamagnetic, paramagnetic or ferromagnetic.
• Superconductors A superconductor can conduct
  electricity without electrical resistance at
  temperatures above absolute zero. Superconductors
  are used in medical instruments such as Magnetic
  Resonance Imaging (MRI) systems.

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Subfields of Materials Science
Introduction to Engineering Materials
Applications

• Ceramics and Glasses High temperature materials
  including structural ceramics such as,
  polycrystalline SiC and transformed toughed
  ceramics. Non-crystalline material includes
  inorganic glasses, vitreous metals and non-oxide
  glasses.
• Composites Materials Composites are formed from
  two or more types of materials. Examples include
  polymer/ceramic and metal/ceramic composites.
  There are three types of composites 1)
  Particulate composites , 2) Laminate composites
  (Tennis rackets) and 3) Fiber reinforced
  composites (e.g. fiberglass)
• Optical Fibers An optical fiber contains three
  layers 1) a core made of highly pure glass with
  a high refractive index for the light to travel,
  2) a middle layer of glass with a lower
  refractive index known as the cladding which
  protects the core glass from scratches and other
  surface imperfections, and 3) an outer polymer
  jacket to protect the fiber from damage.

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Subfields of Materials Science
Introduction to Engineering Materials
Applications

• Fiber-Reinforced Composites are used in some of
  the most advanced, and therefore most expensive,
  sports equipment, such as a time-trial racing
  bicycle frame.
• Advanced Materials Advanced engineered materials
  are playing a major role in the rapid growth of
  the global telecommunication network.
• Nanotechnology It is the creation and study of
  materials whose defining structural properties
  are anywhere from less than a nanometer to one
  hundred nanometers in scale.
• Crystallography The study of how atoms in a
  solid fill space, the defects associated with
  crystal structures such as grain boundaries and
  dislocations, and the characterization of these
  structures and their relation to physical
  properties.

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Introduction to Engineering Materials
Applications
Classification of Materials

• Metals and Alloys Iron and steel,
  superalloys, intermetallic compounds
• Ceramics, Glasses and Glass-ceramics High
  temperature materials. Structural ceramics such
  as, polycrystalline SiC and transformed toughed
  ceramics, Whitewares (e.g. porcelains).
  Electrical Ceramics (capacitors, insulators,
  transducers, etc. Chemically Bonded Ceramics
  (e.g. cement and concrete). Glass,
  Non-crystalline material including inorganic
  glasses, vitreous metals and non-oxide glasses,
  Glass optical fibers,
• Polymers, Thermoplastics and Thermosets Plastics,
  Liquid crystals and Adhesives.
• Electronic, Magnetic and Optical Materials
  (solid-state lasers, LEDs).
• Composite Materials and Biomaterials Man-made
  proteins, biosensors, drug-delivery colloids
  (polymer based)

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Introduction to Engineering Materials
Applications
Functional Classification of Materials

• Aerospace (Composites, SiO2-Amorphous silicon,
  Al-alloys, Super alloys)
• Biomedical ( Titanium alloys, Stainless steels,
  plastics)
• Electronic Materials (Si, GaAs, BaTiO3,
  Conducting Polymers)
• Energy and Environmental Technology (Uo2, Ni-Cd,
  ZrO2, LiCoO2, Amorphous Si-H)
• Magnetic Materials (Fe, Fe-Si, NiZn and MnZn
  ferrites, Co-Pt-Ta-Cr)
• Optical Materials (SiO2, GaAs, Glasses, Al2O3)
• Smart Materials (NI-Ti shape memory alloys)
• Structural Materials (Steels, concrete,
  fiberglass, plastics, wood)

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Periodic Table of Elements
Introduction to Engineering Materials
Applications
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Introduction to Engineering Materials
Applications
Applications, and properties for each category of
materials
Example of Applications
Properties Metals and Alloys Gray cast iron
Automobile engine blocks
Castable, machinable,
vibration damping Ceramics and Glasses
SiO2-Na2O-CaO Window glass
Optically transparent,
thermally insulating Polymers Polyethylene
Food packaging Easily formed into
thin, flexible, airtight
film Semiconductors Silicon
Transistors and integrated Unique
electrical circuits
behavior Composites Carbide cutting tools
for High hardness
Tungsten carbide machining
good shock resistance -cobalt (WC-Co)
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Introduction to Engineering Materials
Applications
Classification of Materials-Based on Structure

1. Crystalline material is a material comprised of
   one or many crystals. In each crystal, atoms or
   ions show a long-range periodic arrangement.
2. Single crystal is a crystalline material that is
   made of only one crystal (there are no grain
   boundaries).
3. Polycrystalline material is a material comprised
   of many crystals (as opposed to a single-crystal
   material that has only one crystal). Grains are
   the crystals in a polycrystalline material. Grain
   boundaries are regions between grains of a
   polycrystalline material.

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Introduction to Engineering Materials
Applications
Structure of Materials Technological Relevance
Level of Structure Example of Technologies
Atomic Structure Diamond edge of cutting tools
Atomic Arrangements Long-Range Order(LRO) Lead-zirconium-titanatePb(Zrx Ti1-x )
Atomic Arrangements Short-Range Order (SRO) Amorphous silica - fiber optical communications industry
Nanostructure Nano-sized particles of iron oxide ferrofluids
Microstructure Mechanical strength of metals and alloys
Macrostructure Paints for automobiles for corrosion resistance
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Properties of Materials
Introduction to Engineering Materials
Applications

• Mechanical properties Elasticity and stiffness,
  plasticity, strength, brittleness or toughness,
  and fatigue.
• Electrical properties Electrical conductivity
  and resistivity
• Magnetic properties Paramagnetic, diamagnetic,
  and ferromagnetic properties.
• Dielectric properties Polarizability,
  capacitance, ferroelectric, piezoelectric, and
  pyroelectric properties.
• Optical properties Refractive index, absorption,
  reflection, and transmission, and birefringence
  (double refraction).
• Corrosion, fatigue, and creep properties

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Introduction to Engineering Materials
Applications
Strengths of various categories of materials
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Introduction to Engineering Materials
Applications
Variation of Strengths with Temperature for
various categories of materials
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Introduction to Engineering Materials
Applications
Materials Design and Selection

1. Density is mass per unit volume of a material,
   usually expressed in units of g/cm3 or lb/in.3
2. Strength-to-weight ratio is the strength of a
   material divided by its density materials with a
   high strength-to-weight ratio are strong but
   lightweight.

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