IE 114 Materials Science and General Chemistry

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IE 114 Materials Science and General Chemistry

• InstructorSibel Uludag-Demirer

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SYLLABUS

• Course Description Classification of the
  materials, atomic structure, periodic table,
  molecular structure, bonding in solid materials,
  structure of crystalline solids, mechanical
  properties of the materials, phase diagrams,
  thermal processing of metal alloys, properties
  and use of ceramics, glasses and composites,
  material selection, and design.
• Course Objective The properties and
  characteristics of the materials are important in
  almost every modern engineering design. The study
  of solids and relationships between structure and
  physical properties is therefore an important
  component of engineering education. This course
  provides a conceptual framework for understanding
  the behavior of engineering materials by
  emphasizing important relationships between
  internal structure and properties. It also
  attempts to present a general picture of material
  nature and mechanisms that act upon, modify and
  control their properties.
• Textbook Materials Science and Engineering-An
  Introduction, William D. Callister, Jr., 5th or
  any other upgrade edition, John Wiley and Sons,
  2000.

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SYLLABUS-cont.

• Attendance Minimum 70 attendance of all lecture
  and recitation hours is required by the
  universitys regulations. Absence from a quiz or
  mid-term examination will result in zero grades.
• Quizzes There will be suggested problems for the
  students to study the subjects covered in class.
  Totally four quizzes will be prepared during the
  semester to understand and grade the efforts of
  the students in solving the suggested problems.
  The course is designed including two hour
  recitation for each section. These hours will be
  used to review the concepts given in lecture
  hours as well as to solve problems.

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SYLLABUS-cont (Course
Outline)
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MATERIALS- A SURVEY
1. What materials can you identify around you
? Wood Plastics Steel Aluminum Glass .............
2. Which segments in our daily lives we use
materials? Transportation Housing Clothing Communi
cation Food production and processing ........
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History of Materials

• Earliest humans used naturally existing materials
  for theri needs
• Wood, skin, clay, stone, etc.
• Later on they discovered new techniques to
  produce pottery and metals and to
• alter their properties by heat treatment and by
  adding other substances.
• Recently (last 60 years approximately) they
  understood the relationships
• between the structural elements of materials and
  their properties, which
• formed the basis of producing materials with
  specialized characteristics.
• For example
• Automobiles plastics, glass, composite
  materials, steel and cast
• iron, aluminum, rubber, other metals, etc.

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Materials Used in the Production of Automobiles
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Change in the Average Weight of Automobiles
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Reasons of More Innovative Automobile Design

• a) reduction in weight forced by fuel and
  pollution issues
• b) government regulations on fuel economy i.e.
  USA -
• currently 29 mpg -future ??
• past increases in fuel economy of the automobiles
  obtained
• mainly by downsizing and mechanical design
• 4 speed automatic transmission
• 5 speed manual transmission
• aerodynamic design
• c) today we need lighter (or super) autos
• i) smaller cars
• ii) lighter materials

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• Studying materials

Materials Science Relationships between the
structures and properties of the materials.
Materials Engineering Designing the structure of
a material to produce a predetermined set of
properties
Why do we study materials in an engineering
curriculum Engineers facing design or production
problems are going to be involved with material
selection, which requires basic understanding
about the materials science and engineering.
Civil engineers-structure of a
building Mechanical engineers-design and
production of transmission gears Chemical
engineers-an oil refinery component Electrical
engineers-an integrated circuit
chip Environmental engineers-liner for
landfilling site Industrial engineers-product
cost including expenses during fabrication as
well as raw material and quality
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Classification of Engineering Materials
Materials
Ceramics Oxides, Nitrides, Carbides, Glasses, Grap
hite, Diamond, etc.
Polymers (Plastics)
Metals
Thermoplastic Acrylics, PE, PVC, etc.
Rubber (Elastomer) Poly- urethanes
Thermoset Epoxies, Phenolics,
Nonferrous Aluminum, Titanium, Copper, etc.
Ferrous Cast iron, Steel, Stainless steel,
Composites-reinforced plastics, metal or ceramic
matrix, laminates, others. Semiconductors-Silicon,
Germanium, Gallium phosphor, other. Biomaterials-
biocompatible materials, Co-Cr-Mo, Co-Ni-Mo metal
alloys (for hip)
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Important terms that we use in the course

• Structure arrangement of internal components
• a)Subatomic structure electrons and their
  interactions with nuclei
• b)Atomic structure organization of atoms
• c)Microscopic structure larger groups of atoms
• d)Macroscopic structure elements that can be
  investigated by naked eye.
• Propertyis material specific and independent of
  the size and shape. This is
• about response of the material to a specific
  imposed stimulus.
• For instance mechanical response (deformation)
  to an applied load
• electricalelectrical
  conductivity and dielectric constant
• thermalheat capacity and
  thermal conductivity
• magneticresponse to
  magnetic field
• opticalresponse to light
  radiation
• deteriorative chemical
  reactivity of materials
• Processing transformation of a material, which
  changes its structure.
• Performance is a function of process used and it
  is the behaviour of the material when
• subjected to forces, high temperatures, high
  pressures, etc.

Processing
Structure
Properties
Performance
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Metals

• -pure metallic element or combination of metallic
  elements (alloys)
• -their electrons are highly nonlocalized (not
  bound to any particular atom or nuclues.)
• -good conductors of electricity and heat
• -not transparent to visible light
• -strong but deformable
• -all metals form crystalline structure under
  normal solidification conditions.

Atoms are situated in a repeating array over
large atomic distances.
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Ceramics

• -are compounds formed by metallic and nonmetallic
  elements (oxides, nitrides,
• carbides), such as, cement, clay minerals, glass.
• -hard, but brittle
• -insulates heat and electricity
• -highly resistant to high temepratures and harsh
  environments compared to metals and polymers
• -are usually crystalline in structure.

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Polymers

• -are familiar plastic and rubber materials
• -are organic compounds composed of C, H and other
  nonmetallic elements
• -have very large and flexible molecular
  structures, low densities
• -they may be crystalline in theri structure to
  some degree, but they are typically
  noncrystalline.
• Naturally existing strach, enzyme, cotton, wool,
  leather, silk, cellulose.
• Polymer molecules are gigantic compared to
  hydrocarbons (molecules made of H and C) and
  formed on a string of carbon atoms (the
  backbone)

MER unit
If, for example, ethylene is subjected to
appropriate T an P conditions in the existence
of a catalyzor, it will transform to
polyethylene (PE).
Active mer
Initiator (catalyst)
ethylene
MER
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Polymers-cont.
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Polymers-cont.

• If the monomer bonds with two other units,
• it is called bifunctional.

ethylene
If the monomer bonds with three other units, it
is called trifunctional.
Phenol-formaldehyde
If the repeating units are of the same type along
the chain, it is called homopolymer, while the
polymer composed of two or more mer units is
called copolymer.
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Polymers-cont.

• Molecular Weight of the Polymers
• The molecular weights of the polymers are large.
  Since not all chains can grow
• to the same length during the synthesis of the
  polymer, there is a distribution of
• chain lengths and molecular weights as a result.
• One way of calculating molecular weight is the
  calculation of number-average molecular weight

Mean (middle) molecular weight of size range i
Fraction of the total number of chains within
the specified size range, i.
Number-average MW
Another way of calculating MW is the calculation
of weight-average molecular weight.
Weight-average MW
Weight fraction of molecules within the specified
size range, i.
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Polymers-cont.
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Polymers-cont.
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Polymers-cont.

• Average chain size of a polymer can be expressed
  as degree of polymerization, n.
• naverage number of mer units in a chain.

Number average degrees of polymerization
Weight average degrees of polymerization
Mer molecular weight
For a copolymer the mer molecular weight
Molecular weight of mer j
Chain fraction
Various characteristics of polymers depend on MW
melting and softening temperature. Polymers with
very short chains (MW to be about 100 g/mol)
exist as liquids or gases at RT. Polymers with MW
of 1000 g/mol are waxy solids (paraffin wax),
while those with 10,000 g/mol to several million
of MW or higher are solid (high polymers).
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Polymers-cont.

• Shape Polymer chains are not strictly straight,
  which makes the material capable of rotating and
• bending in 3-D.

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Polymers-cont.
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Polymers-cont.

• Some of the mechanical and thermal
  characteristics of polymers are related with the
  ability of the chain segments to rotation in
  response to stress and thermal vibrations.
• For example the region of a chain segment that
  has a double bond is rotationally rigid or
  introduction of a bulky side group restricts the
  movement. Polstyrene molecules molecules are more
  resistant to rotational movement than PE chains
  since it has a phenyl side group.

polystyrene
Structure The physical properties of polymers
are affected by the structure of the molecular
chains.
Linear polymers Mer units are joined together
end to end in single chains. They are flexible.
There may be extensive van der Waals forces or
hydrogen bonding between the chains, which
affects the strength of the material. PE, PVC,
nylon...
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Polymers-cont.

• Branched polymers those are the polymers
• synthesized in which side-branch chains are
• connected to the main chain. Branching lowers
• the density of the polymer.

Crosslinked polymers Linear chains are joined
to another at various positions by covalent
bonding. Rubbers
Network polymers Trifunctional mer units form
this type of structure. Epoxies,
phenol- Formaldehyde.
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Polymers-cont.Classification of polymer
characteristics
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Polymers-cont.

• The response of a polymeric material to
  mechanical forces at high T conditions allows one
  more
• classification for this material.
• Thermoplasts they soften when heated and harden
  when cooled and this process is reversible. If
  the temperature raised upto a point at which the
  primary covalent bonds are broken, then the
  process becomes irreversible. Most of the linear
  polymers are in this group.
• Thermosets They become permanently hard when
  they are heated and do not soften as the heating
  process continues. They are harder and stronger
  than thermoplasts and have better dimensional
  stability. Most of the crosslinked and network
  polymers are in this group.

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Composites

• A composite is a multiphase material that is
  artificially produced. The phases are chemically
• dissimilar and separated by a distinct interface.
  

Many of the composite materials are composed of
two phases one is matrix and the is dispersed
phase (reinforcement).
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Composites-cont.
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Composites-cont
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• References
• Textbook, Callister, 2000.
• Smith, 2006.