Materials Science and Engineering

Crystallographic planes

1 (miller indices) 2) if plane goes through orgin => move orgin 3) take reciprocal 4) orgin to x, orgin to y, orgin to z

Crystallographic directions

1 (x,y,z vector) 2) reduce to smallest interger value

rock salt

1) (NaCl) 2) AX structure 3) 5,4,5 cation (z=1,z=2,z-3) 4) CN = 6

cesium chloride

1) CsCl 2) AX structure 3) looks like BCC with centered cesium 4) CN = 8

4 types of co-polymers

1) block polymer 2) graft polymer 3) alternating copolymer 4) random copolymer

four component of solid oxide fuel cells

1) cathode 2) anode 3) electrolyte 4) interconnect

2 directional bonding types

1) covalent 2) secondary (vander wals)

4 strengthening mechanisms for polymers

1) higher molecular weight 2) higher % crystallinity 3) side groups or secondary bonding 4) deforming polymer

2 ways that heat is asorbed

1) increased vibration amplitude of atoms 2) increased kinetic energy of electrons

2 non directional bonding types

1) ionic 2) metallic

eutectoid

1) one solid phase transforms to two other solid phases 2) all solid

solid solution rules (hume rothery)

1) same atomic size (within %15) 2) same crystal structure 3) same electronegativity 4) same valences

strengthening mechanisms

1) solid solution ( alloying with impurties = change in structure) 2) strain hardening (plastically deformed = cold working 3)grain size reduction (makes grain boundary smaller for dislocation motion)

Perovskite

1)BaTiO3 2) AB X3 structure 3) box Ba, cross O, centered Ti 4) CN = 4

Flourite

1)CaF2 2) A X2 structure 3) big box 4) CN = 8

Zinc Blende

1)ZnS 2) AX structure 3) 5,2,4,2,5, (z=1,z=2,z=3,z=4,z=5) 4) CN = 4 5) ex = diamond

FCC Coordination number

12

HCP Coordination number

12

BCC atoms per cell

2

FCC atoms per cell

4

BCC edge length

4R/(sqrt(3))

HCP atoms per cell

6

BCC APF

68%

FCC APF

74%

HCP APF

74%

BCC Coordination number

8

If a material is stressed past sigma yield then it has 1) elastic deformation 2) plastic deformation 3) both

Both

equation for flux

J = M / At

H H I I C ----- C I I H Cl

PVC

F F I I C ----- C I I F F

Teflon

solute

The substance that is dissolved

eutectic

When 2 solids are mixed together to form a liquid

weight percent

[ m1 / (m1 +m2) ](x100)

FCC edge length

a = 2R(sqrt(2))

solvent

a liquid substance capable of dissolving other substances

toughness

area under entire curve (ultimate)

resilience

area under linear portion of curve (under yield point)

isotactic

arrangement of side groups

thermal expansion is caused by _______

asymmetry of bond energy curve

moles (n)

atomic mass / atomic weight

coordination number

atoms touching unit cell. ex (FCC = 12) (BCC = 8)

tempered martensite heat treatment

austenitize, quench, heat from 250-650 and hold for 2 hours. cool to room temp.

how are glasses and ceramics tested

bending test

bainite

cool to ~450

fine pearlite

cool to ~550

coarse pealite

cool to ~650

polycrystalline

crystaline solid composed of many small crystals or grains

7 crystal systems

cubic, hexagonal, tetragonal, rhombohedral, orthohombic, monoclinic, triclinic

melting temperature (inceases/decreases) as solute is added

decreases

material that's tetrahedrally coordinated

diamond

slip

dislocation motion

How does ceramic charge impact dislocations

dislocation slip is very difficult => tougher & brittle

high oredered polymers are (easier/harder) to crystallize

easier

linear defects (dislocations)

edge and screw

allotropy

elemental solids having more than one crystal structure

solid solubility increases with temperature up to what point

euectic temperature

polymers form long range order by _______

folding

below Tg, polymers are ______

glassy

material that is three fold coordinated

graphite

spheroidite heat treatment

heat to just below eutectoid and hold for long time (4 days)

interatomic distance (increases/decreases) with temperature

increases

amorphous

lacks arrangement of atoms (without form)

peritectic

liquid and one solid phase transform to a second solid phase

equation of weight percent

m1 / (m1+m2)

crystalline

material's atoms are in repeating pattern or periodic array over large atomic distnces

isotropic

measured properties are independent of direction

at what point is there no driving force for nucleation

meting point

interfacial defects

mismatch between adjacent grains

equation for number of moles

n = Mass / atomic wt (M/A)

equation of atomic percent

n1 / (n1 + n2)

heterogeneous nucleation

nuclei form at surface, on walls, boundaries ect.

homogeous nucleation

nuclei form uniformly in substance

Frankel Defect

one cation vacancy & cation interstitial

Schottky defect

one cation&anion vacancy pair

H H I I C ----- C I I H H

polyethylene

crystallization

producing fine grained ploycrystaline (glass ceramic)

ansiotropy

properties are dependent on direction

above Tg, polymers are ____

rubbery

what are the corresponding shell numbers for s,p,d,f

s = 0 p = 1 d = 2 f = 3

What size of atoms are prone to be interstitial

small

viscoelastic deformation has much (smaller/larger) modulus than in metals

smaller

delta G is stronly dependant upon________

temperature

diffusion coefficient is exponentially dependant on _____

temperature

polymers that are linear or branched

thermoplastic

polymers that soften upon heating

thermoplastic

polymers that are crosslinked and networked

thermosets

polymers that harden upon heating

thermosets

anelasticity

time depenent elasticity

Diffusion mechanisms

vacancies and interstitials

point defects

vacancies and self interstitials

polymorphism

when metals or nonmetals have more than one crystal structure