difference btween atomic structure and crystal: bohn model, consist proton, electron, & arragement of atom.
ionic bonding: transfer electron
covelent bonding: share electron
metallic bonding: cloud of electron
density: nA/VNa
APF: n(4/3pia^3)/volume
volume: a^3
A=atomic mass
nSC=1, nBCC= 2, nFCC=4, nHCP=6
Asc= 0.5a, BCC= punca 3a/4, FCC= punca 2a/4
APF: sc=0.52, BCC=0.68, FCC= 0.74, HCP= 0.74
metal: close packing,metallic bonding,large atomic mass
ceramic: less dense packing density, lighter
polymer: low packing density, lighter element
diffusion: J=-D dc/dx
defect: point, line, area
point defect: vacancy atim, interstitial, subtitutional atom
line defect: dislocation: edge & screw
area defect: twin boundary
stress: tho(psi)= sigma cos lamda cos phi
increasing strength:
1 reduse grain size
2 solid solution(alloying)
3 precipitation
4 cold work
%cw = A0-Ad/Ad *100%
cw up, yield strength up, tensile up, ductility down
effect of cold work
1 recovery
2 recrystallization
3 grain growth
mechanical properties:
stress: force / area
strain: stress/ length displacement
elastic: reversible
plastic: permenent
toughness: energy to break a unit volume material
ductility: plastic tensile strain at failure
resilience: ability material store enrgy
hardness: resistance to permanent indenting surface
modulus elastic: E= stress/ strain
elastic shear modulus: G= tonsion stress/ shear strain
saturated hydrocarbon: single bond
unsaturated hydrocarbon: double or triple bond (less stable)
degree of polumerization:
Mn= sum XM
Mw= sum WM
nn= sum Xn/m
nw= sum Wn/m
m= average molecular weight= sum fm
increasing strength:
linear-branched-crosslinked-network
copolymer: 2 or more monomer polymerized together
thermoplastic:
little crosslinked, ductile, soften when heating, small e, large kc
thermoset:
more crosslinked, brittle,does not soft when heat, lagre e, small kc
defect in ceramic:
1 frenkel defect: a cation is out of place
2 shotty defect: a pair of cation and anion missing
advance ceramic application: SiC
1 heat engine
2 ceramic armor
3 electronic device
heat engine:
advantages: run in higher temperature, excelent wear and corrosion resistance, ability run without cooling system
disadvantages: brittle, too easy to have void-weaken engine, diffucult to machine
purpose matrix: transfer stress to other phase, and protect phase from enviroment
purpose dispersed phase: help enhance matrix properties
MMC= up stress, tensile strength and creep resistence
CMC=up kc
PMC= up e stress, tensile strength
Ec=VmEm+VpEp
1/Ec= Vm/Em + Vp/Ep
definition biocompatibility: the ability of material to perform with an aprociated host response in a specific application
implant factor:
1 bulk properties
2 surface properties
3 mechanical properties
4 long term condition
host factor:
1 species
2 age and healthy
3 immunology
stainless steel:
1 ferritic (BCC)
2 austenitic (FCC)
3 martensitic (BCT)
*kurang stdy bab nie..mlm nie br nk ingat all
bab seterus nye ak dh xdpt ingat sgt..atas nie pon penat ak recall br dpt ingat..definition and rumus kn remember lagi..otak ku kn terima semua ini..huuhuuu...
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