Introduction Flashcards
What are the three types of materials
Metals, ceramics, polymers, and semiconductors
What are the structures of materials in different scales
atomic, microscopic, macroscopic
What are the different properties of materials
6: mechanical, thermal, electrical, optical, magnetic and deteriorative
Whats material science vs engineering
science: studying structures and properties and their relation
engineering: designing structures with pre-determined properties
Explain the subatomic level
electronic structure of each atom that defines the way they interact among other atoms
Explain the atomic level
how atoms are arranged in materials (isotopes)
Microscopic vs microscopic
micro: small
macro: naked eye
metric system conversion
T G M k h da Base d c m u n p
How much is an angstrom? What is it used to measure?
10^-10m
inter-atoms
What prefix used to measure microelectronics? Quantum dot? cellular shit
micrometer, nanometer/micro, nanometer
What are the different properties?
Mechanical, electrical, thermal, magnetic, optical, deteriorative/chemical
Describe mechanical properties
Modulus (how elastic) , toughness, strength, hardness
What is modulus
How elastic something is
Describe electrical property
conductivity, resistivity, dielectric constant (amount of electric potential energy)
Describe thermal property
heat capacity, thermal expansion, thermal conductivity
Describe magnetic property
Diamagnetic: not attracted to external magnetic fields
paramagnetic: attracted to external magnetic fields
ferromagnetic: highly attracted to external magnetic fields
Describe optical properties
reflectivity, absorption (opaque, translucent, transparent), transmission
What is optical transmission
using light to travel through an optical fiber, converting it into electrical signals as the receiver (form of communication)
translucent, opaque, transparent
Describe deteriorative and chemical properties
Oxidation, corrosion, irradiation (exposing to radiation)
How do properties, structure and processing relate
properties depend on structure. Processing can change the structure
electrical resistivity of copper with temperature and impurities
the more impurities, deforming and inc temperature, the more resistive it is
what happens when you add zinc to copper
increases thermal conductivity
What makes aluminum oxide different light transmissions
single crystals allows for light to be transparent high degree of perfection
lots of polycrystals low porosity: translucent; lots of small single crystals connected, boundaries scattering light from printed page
lots of polycrystals high porosity: opaque; lots of small interconnected cyrstals with pores that scatter light
Describe metals
has valence electrons detached from atoms and spread in electron sea
Good conductors, of heat and electricity
tough, strong and deformable
Dense
What’s ductile
deformable
Describe semiconductors
The bonding is covalent.
semmi CONDUCTORS
sensitive to impurities
Describe ceramics
either behave like positive or negative ions and bond by Coulomb forces.
Made of metals atoms and oxides, nitrides and carbides (CON)
Insulator of heat and electricity
Hard but brittle
Describe polymers
large organic molecules based on carbon, hydrogen, other nonmetallic
Plastic, rubber,
soft, flexible, light
Describe composites
Combination of metals, ceramics and polymers
Describe fiberglass properties
flexible fiber, strong glass
Material selection process
Choose what properties you want
Choose what materials have those properties
Choose the process your use to obrain a better product and to get shape
What are the differnt processes of making a material
Casting, Sintering( to heat and compress without liquifying), vapor deposition, doping forming (adding impurities), annealing (heat treating to change physical and chemcal properties)
Characteristics of nanostructured matierals
1 and 100 nm with unsusual properties
Like electronic components for quantum computing
What’s special about shells and mollusces
shells are hard tissue, mollusks produce powerful adhesive
cutting vs etching
cut, engraving
Whats bottom up vs top bottom?
bottom up is building things from basic level since we have microscopes
how bit are biomolecules and inorganic clusters?
5-15nm
What are smart materials
have a sensor and an actuator (performs responsive and adaptive function like change shape, temp etc)
Not important: what are the four types of materials used for actuators
shape-memory alloys (metals): change shape with temperature
piezoelectric ceramics: expand and contract with electric field (voltage)
magnetostrictive materials: analogous to piezoelectrics but respond to magnetic field
electorheological/magnetorheological fluids: different viscosity with application of electric and magnetic fields
Whats an alloy
a combination of two or more elements (usually metals)
