Materials Science and Engineering Flashcards
paradigm of mat sci and eng
processing -> structure -> properties -> performance
structure of a material usually relates to the arrangement of its internal components
structure
material traits in terms of the kind and magnitude of response to a specific imposed stimulus
properties
relate deformation to an applied load of force
mechanical properties
relates the applied electric field
electrical properties
temperature changes and temperature gradients across the material
thermal properties
relates the applied magnetic field
magnetic properties
relates the electromagnetic or light radiation
optical properties
relate to the chemical reactivity of materials
deteriorative properties
represented in terms of heat capacity and thermal expansion
thermal behavior
pertains to the electrons within individual atoms, including their energies and interactions with the atomic nuclei
subatomic structure
refers to the arrangement of atoms, which leads to the formation of molecules or crystals
atomic structure
focuses on the study of aggregates of atoms that come together to form particles which have nanoscale dimensions
nano-structure
structural elements that can be directly observed using a microscope
microstructure
refers to the structural elements that can be observed with the naked eye
macrostructure
composed of metallic elements; atoms are arranged in a very orderly manner
metals
compounds between metallic and nonmetallic elements; most frequently oxides, nitrides, and carbides
ceramics
compounds composed of primarily carbon, hydrogen and other nonmetallic elements; large molecular structures chainlike nature with backbone of carbon atoms
polymers
low density, low stiffness and strength, extremely ductile and pliable, good deteriorative properties: relatively inert chemically
polymers
composed of at least two different material types
composites
__ tend to have lower energies = better stability
dense, ordered packed structures
atoms/ions in repeating or periodic array over large atomic distances
crystalline materials
lack periodicity and long-range order; have complex structure; formation is favored thru rapid cooling
noncrystalline materials (amorphous)
tend to be densely packed; simpler than that of ceramics and polymers
metallic crystal structure
rare due to low packing density; close-packed directions are cube edges
simple cubic structure
number of nearest-neighbor or touching atoms
coordination number
two or more distinct crystal structures for the same material
polymorphism; allotropy for elemental solids
reciprocals of the 3 axial intercepts for a plane, cleared of fractions and common multiples
miller indices
determination of crystal structure and interplanar spacing; incoming x-rays diffract from crystal planes
x-ray diffraction
loads may be applied primarily in three ways
tension load, compressive load, shear load
nonpermanent deformation
elastic deformation
permanent deformation
plastic deformation
measure of the resistance to separation of adjacent atoms - interatomic binding forces
modules of elasticity
shear strain-strain relationship
shear modulus
relates the lateral and axial strains
poisson’s ratio
also known as proportionality limit, initial departure from linearity of the stress-strain curve
yielding
stress at which noticeable plastic deformation has occurred
yield strength
max stress that can be sustained
fracture
measure of the degree of plastic deformation that has been sustained at fracture
ductility
materials are said to have very little to no plastic deformation upon fracture
brittle materials
exhibit plastic deformation before finally fracturing
ductile materials
abundant within earth’s crust; economical processing techniques; extremely versatile
ferrous alloys
most widely used engineering construction materials
ferrous alloys
relatively soft+ductile+tough; machinable, weldable; automobile body components, structural shapes, sheets for pipelines
low-carbon steels
stronger than low-carbon steels; poor ductility and toughness
medium-carbon steels
hardest, strongest but least ductile; cutting tools and dies for forming and shaping materials, knives, razors, etc
high-carbon steel
alloyed by Cr to improve corrosion resistance; further improve by addition of Ni and Mo; highly resistant to corrosion, consequently leads to its wide range of applicability
stainless steels
similar to steels but with higher carbon contents > 2.14%
cast irons
graphite form: flakes; weak and brittle under tension; strong and ductile under compression
gray cast iron
in nodules or sphere like form; also called as nodular iron
ductile iron
carbon exists as cementite; extremely hard, very brittle
white cast iron
graphite form is wormlike/vermicular; tensile and yield strengths are comparable to ductile and malleable iron; high thermal conductivity, better resistance to thermal shock, and lower oxidation at high T
compacted graphite iron
corrosion resistant; Zn as alloying component
brass
Sn, AL, Si, Ni as alloying component; corrosion resistant + added strength
bronze
low density, high electrical and thermal conductivities, corrosion resistant for some common conditions, high ductility
aluminum and its alloys
low density, relatively soft
magnesium and its alloys
low density, high melting point, extremely strong, highly ductile, highly machinable
titanium and its alloys
achieved through firing, a high-temperature heat treatment process of materials
ceramic
stable structure is where cation is with __ nearest neighbor anions; cations that are all contact with the __
high; anion
noncrystalline or amorphous silicates containing other oxides such as CaO, Na2O, K2O, Al2O3
glasses
widely used ceramic raw material; inexpensive and abundant
clay products
can withstand high temperatures without melting/decomposing; remain unreactive under extreme conditions
refractories
extremely hard and war resistant; mohs hardness>7
abrasives
characteristic feature of setting and hardening when mixed with water
cements
study crack origins and configurations of brittle ceramics for different loading types
fractography
polymer composed of single type of repeat units
homopolymer
polymer composed of 2 or more different repeat units
copolymer
properties of polymers depend on:
molecular weight, shape, structure of molecular chains
chain bending and twisting are possible by rotation of carbon atoms around their chain bonds
molecular shape (or conformation)
fractures while deforming elastically
brittle polymers
similar to most metals which includes elastic deformation followed by plastic deformation
plastic polymers
deformation is totally elastic in which there is large recoverable strains produced at low stress level
elastomers
the stress corresponding to the maximum point just after the linear-elastic region
yield strength
tensile strength, which corresponds to the stress at which fracture occurs
strength of polymer
show physical manifestations like those of metals, known as crazing
fracture of polymers
doping where dopant is donor impurity atoms
n-doping
n-doping dopants
P, As, Sb
p-doping dopants
B, Al, Ga
doping where dopant is acceptor atoms
p-doping
major charge carrier for n-doping
electrons
major charge carrier for p-doping
holes
substances that are, or have been, reduced in size to the range from 1 nm to ~100 nm
nanomaterials
nanomaterial dimension where all dimension (x,y,z) is within the nanscale range
0D
nanomaterial dimension where 2 of 3 dimensions are in nanoscale range
1D
nanomaterial dimension wherein 1 dimension is in the nanoscale range
2D
nanomaterial dimension where dimensions are not confined in any direction’ still considered as nanomaterials since they are made up of individual particles in the nanometer scale
3D
