MATERIAL SCIENCE AND ENGINEERING

• Material Science


  It tackles relationships between the structures and properties of a material
• Material Engineering


  Designing, engineering structure of a material to produce pre-determined set of properties
• Components of Material Science and Engineering

  • Structure
  • Property
  • Performance
  • Processing
  • Characterization
• Structure


  • Refers to the level of arrangement of its component
  • Subatomic level - electrons, protons, neutrons
  • Atomic level - elements in periodic table & atomic structure
  • Microscopic level - large group atoms that are bonded together
  • Macroscopic Level - can be viewed by naked eye
• Property


  • Material trait in terms of the kind and magnitude of response to a specific imposed stimulus
  • Mechanical Property - relates to deformation to an applied force
  • Electrical Property - electrical conductivity and dielectric constant
  • Thermal Property - Heat capacity of a material
  • Magnetic Property - response of a material to a magnetic field
  • Optical Property - response of a material to EM wave LIGHT
  • Deteriorative Property - chemical reactivity of a material
• Performance


  Function or application of its properties
• Processing


  Method to develop the material
• Characterization


  Those 4 components define the characteristics of a material
• Why study material science

  • Material Selection
  • New Material Fabrication
  • Material Investigation
• Classification of Solid Materials

  • Metals
  • Ceramics
  • Polymers
  • Composites
• Metals


  • Relatively strong, stiff, ductile
  • Resistant to fracture
  • Good Conductors
• Ceramics


  • Relatively strong, stiff, hard
  • Extremely brittle
  • Insulative to heat and electricity
• Polymers


  • Not strong, stiff
  • Extremely ductile
  • Can easily be deformed
• Composites


  • Combination of the combined best characteristic of each material
• Composition of Materials


  • Metals - composed of metallic elements
  • Ceramics - most frequently composed from oxides, nitride, carbides
  • Polymer - includes plastic and rubber materials, based on carbon, hydrogen, and other non-metallic elements
  • Composites - the design goal is to achieve a combination of properties that is displayed by a single material
• Classification of Advanced Materials

  • Semiconductors
  • Biomaterials
  • Smart Materials
  • Nanomaterials
• Semiconductors


  • Possess electrical properties that are between conductor and insulators
  • Extremely sensitive to concentration of impurity atoms
  • Revolutionized electronics and computer industry
• Biomaterials


  • Employed in components that are implanted to a human body to replace damaged or deceased body parts
• Smart Materials


  • Called smart because it can sense change to its environment and then respond to these changes in a pre-determined manner
  • Has a sensor and an actuator
• Nanomaterials


  • Nano prefix due to the structural entities are in the order of nanometer
• Atomic Structure


  Atoms are consisting of very small nucleus composed of protons and neutrons that are encircled by electrons
• Sub-atomic Particles


  • Electrons - Charge: -1.609x10-19C, Mass: 9.11x10-31 kg
  • Protons - Charge: +1.609x10-19C, Mass: 1.67x10-27 kg
  • Neutrons - Charge: Chargeless, Mass: 1.67x10-27 kg
• Atomic Number (Z)


  Represents the number protons in the nucleus which is equal to the electrons outside the nucleus
• Atomic Mass (A)


  Represents the sum of number of protons and neutrons
• Isotope


  Elements with the same atomic number and different atomic mass
• Atomic Weight


  Corresponds to the weighted average of the atomic masses of the atom's natural occurring isotopes
• Atomic Weight Unit


  1 mol is equal to 6.022x10^23 atoms, called Avogadro's numbers
• Building Blocks of an Atom


  • Isobars - elements with same atomic mass but different atomic number
  • Isomers - elements with the same molecular formula but different structures
  • Isotones - elements with the same number of neutrons but different number of protons
  • Isotopes - elements with the same atomic number but different atomic mass
• Bohr Atomic Model


  States that electrons are assumed to revolve around the atomic nucleus in discrete orbitals
• Quantum Numbers

  • Principal Quantum Number (n) - Relates to the distance of electron to the nucleus
  • Azimuthal Quantum Number (l) - Relates to the shape of the subshell
  • Magnetic Quantum Number (ml) - Determines energy state of the subshell
  • Spin Quantum Number (ms) - Orientation of electron either upward or downward direction
• Pauli's Exclusion Principle


  No electron can be identified by the same set of quantum numbers
• Aufbau Principle


  Electrons fills the lowest energy level before filling the higher energy level
• Hund's Rule


  Every orbital in a particular sublevel is initially occupied by a single electron before any orbital is double occupied
• Electron Configuration


  Structure of an atom that represent the way states are occupied
• Periodic Table Groups


  • Group IA - Alkali Metals
  • Group IIA - Alkaline Earth Metal
  • Group IIIB-IIA - Transition Metals
  • Group IIIA-VIA - Semi Metals
  • Group VIIA - Halogens
  • Group 0 - Noble Gasses
• Electropositive Elements


  Elements under metal classification, gives up electron to form positive ions
• Electronegative Elements


  Elements above metal classification, accepts electron to form negative ions
• Interatomic Bonding


  • Ionic Bonding
  • Covalent Bonding
  • Metallic Bonding
• Ionic Bonding


  • Found in compounds of metallic and non-metallic elements, occurs between positive and negative ions, attractive bonding force between positive and negative ions termed as Coulombic force
• Covalent Bonding


  • Chemical bonding that is most commonly occurring for non-metallic elements, results from sharing of valence electron