Midterm 1 Flashcards
Properties of Materials (6)
Mechanical, Thermal, Optical, Magnetic, Environmental, Electrical
Mechanical Properties Need to Know (6)
Yield Strength, Youngs Modulus, Ultimate Tensile Strength, Fracture Strength, Ductile, Toughness
Triangles and Direction
Properties, Structure, Processing, Performance
Which In the Triangle Is Science
Structure and Properties
Which in the Triangle is Engineering
Processing and Performance
Primary Materials
Metal, Ceramic, Polymer
What Bond is Metal
Metallic
What Bond is Ceramic
Ionic
What Bond is Polymer
Covalent
Properties of Metal
Dense, Strong, Reflective, Opaque, High Thermal and Electrical Conductive, Medium Melting Point, Can Corrode
Properties of Ceramic
High Melting Point, Resistor, Brittle, Corrode Resistant, Glassy, Inelastic, Medium Density
Polymer Properties
Corrode Resistant, Low Density, Soft, Ductile, Thermal and Electrical Conductive, Translucent or Transparent
Which is stronger Faster Cooling Or Slower
Faster Cooling is Stronger
Atomic Structure
Proton Electron Neutron
Charge of Proton
Positive
Charge of Electron
Negative
Charge of Neutron
Neutral
Isotopes
Element with 2 or more different atomic masses
Quantum Number N
Principle (energy shell level)
Quantum Number L
Subsidiary (Orbitals)
Quantum Number m_L
Magnetic
Quantum Number m_s
Spin
Value of L
N-1
Value of m_l
(+-)L
Max electrons in subshell
s=2 p=6 d=10 f=14
Higher level electron rule
After 3p 4s 3d
Which section of the periodic table gives and which takes
Bottom left gives more upper right takes
Which bonding is directional
Covalent
Why are metals strong even if the bond is weak
They are densely packed because they are non directional and ordered packing
SC unit cell length
2r
fcc unit cell length
2rad2
bcc unit cell length
4/rad3
2d coordinate number
4
sc coordinate number
6
fcc coordinate number
12
bcc coordinate number
8
Atoms per unit cell 2d
1
atoms per unit cell sc
1
atoms per unit cell fcc
4
atoms per unit cell bcc
2
Atomic Packing Factor Formula
((2)(4/3)(r^3))/a^3 a = cell length
Atomic packing factor sc
.52
atomic packing factor fcc
.74
atomic packing factor bcc
.68
theoretical density formula
(atoms/unitcell)(g/mol)/(a^3)(6.022*10^23)
Four Axis System
U = (1/3)(2u-v) V=(1/3)(2v-u) T = -(U+V) W=w
Planes
Take reciprocal, reduce out of fraction
X-ray defreaction
n(wavelength)=2dsin(angle)
space between hkl
a/rad(h^2+k^2+l^2)
defraction angle
2(theta)
Vacancy
empty site in structure
Equilibrium Vacancy Concentration
density = nA/(V_c)(N_A) = NA/(VN_A)
N_v/N=exp(-Q_v/kT)
N_v = number of vaccants N= total atomic sites Q=Activation energy k = Boltzmans constant T = temperature
interstitals
Extra atoms
