Introduction to Materials Science (MATS 201)

1
??????????????
????? 4
2

• 0 ???? ????????????????? (point defect)
• 1 ???? ?????????????????? (dislocation)
• 2 ???? ??????????????????????????????????????
  ??????????? ??????????????????????????????? ????
  ???????? ?????? ???????????????????????????

3
?????????????????????? (Point Defect)
?????????????????????????? ???????????????????????
?????????????? 1. ?????????????????????????????
???????????????????? ??????????????? (Vacancy)
2. ?????????????????????????????????????????????
??????? ???? (Interstitial Impurity
Atom) 3. ????????????????????????????????????????
(Substitutional Impurity Atom)
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Point Defect Vacancy
??????????????????????????????????????????????
(vacancy) ????????????????????????????????????????
?? vacancy ????????????????????????????????????
? ?????????????????????????????????????????????
(solidification) ?????????????? ???????????????
???? vacancy ???? ????????????????????????????????
?? ??????????????? exponential
http//www.soton.ac.uk/engmats/xtal/deformation/v
acancy.gif
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nv ????? vacancy/m3 n ????? lattice
point/m3 Q ??????????????????????? vacancy
(J/mol) R gas constance 8.31 J/mol/K T
Temperature (K) ??? thermal energy ????????????
Tm ??????????? vacancy 1 vacancy per 1000
lattice point
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Point Defect Interstitial Defect

• ??????????? extra atom ???????????????? lattice
  structure
• Interstitial atom lt atom located at lattice point
  ??? gt interstitial site ????????????????
  ??????????? lattice ??????????? ????
  ????????????????????

www.soton.ac.uk/.../deformation/introduction.htm
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Point Defect Substitutional Defect

• ????????????????????????????????????
• ????????????????? ??????????????????????????????
  lattice ???????????????????? ?????? ????
  ??????????????????? ???????????????????? ??????
  ????????????????????????????????????????
  ??????????????????????????? (impurities)

www.soton.ac.uk/.../deformation/introduction.htm
http//www.doitpoms.ac.uk/tlplib/dislocations/imag
es/substitutional-solute.gif
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Interstitialcy Defect

• ?????????????????????????? (????????????????????
  lattice point) ??????????????? interstitial
  position
• ???? defect ??????????? lattice ????? low packing
  factor

??????????????????????????????????????????????????
??????????????????????????????????????
??????????????????????????????????????
????????????????????? ???????????????????????????
?????????????????????????????????
??????????????????????????????????????????
??????????????????????????????????????
???????????????????????? ??????????????????
??????????????????????????????????????????????????
???? (Semiconductor) ???
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????????????????????? (Frenkel Defect)
Frenkel defect ??????? ?????????????? normal
lattice point ???????????? interstitial site
????????????? vacancy
https//www.chemistry.ohio-state.edu/woodward/ch7
54/lect2003/ionic_cond_lect26.ppt
http//www.gprecision.net/metallurgy-Defect-Crysta
ls.html
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????????????????????? (Schottky Defect)
?????????????????????????????????????????????
?????????????????? ??????????????????
????????????? ? ??? ?????????????????
??????????????????????????????????????????????????
??
Schottky defect ??????????????????????????????
?? ???????? anion cation ???????? lattice
???????????? electrical neutrality
????????????????
http//www.gprecision.net/metallurgy-Defect-Crysta
ls.html
https//www.chemistry.ohio-state.edu/woodward/ch7
54/lect2003/ionic_cond_lect26.ppt
www.bss.phy.cam.ac.uk/amd3/teaching/A_Donald...
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http//www.doitpoms.ac.uk/tlplib/dislocations/imag
es/raft3.jpg
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Dislocation

• ???? linear imperfection ?????????????????????????
  ? solidification ???????? ????????????????????????
  ?????
• ?????????????????? ?? 2 ???

http//www.tf.uni-kiel.de/matwis/amat/def_ge/kap_5
/illustr/dislocation_3dim.jpg
http//www.siliconfareast.com/screwdislocation.jpg
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Screw Dislocation
??????????????????????????????????????????????????
???????????????????????????
http//www.material.science.sudeshnapaul.com/screw
_dislocation.gif
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Edge Dislocation
www.klingereducational.com/index.php?pproduc...
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http//courses.eas.ualberta.ca/eas421/diagramspubl
ic/bergerslarge.gif
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http//www.roymech.co.uk/images10/mixed_dislocatio
ns.gif
http//www.bss.phy.cam.ac.uk/amd3/teaching/A_Dona
ld/Crystalline_Solids_1.htm
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????????? dislocation ?????? slip direction
????????????????? Burgers vector ??? Edge
dislocations
www.ic.arizona.edu/.../disclocation.html
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www.tf.uni-kiel.de/.../backbone/r5_1_3.html
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Surface defect
http//www.scielo.br/img/revistas/mr/v6n2/16034f4.
gif
www.cartage.org.lb/.../Crystalline.htm