bab 4_cacat kristal

7/25/2019 Bab 4_Cacat Kristal

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CACAT KRISTAL

IMPERFECTIONS OF SOLIDS


2/39

Presentasi ini disusun berdasarkan

buku Callister 7ed;

presentasi ppt dari www.en.bilkent.edu.tr

!"#apter$%&$a'i

presentasi ppt dari www.en(ineer.ta)uk.edu!"#apter

%&$a'i$ er)an
http://www.fen.bilkent.edu.tr/http://www.engineer.tamuk.edu/chapterhttp://www.engineer.tamuk.edu/chapterhttp://www.fen.bilkent.edu.tr/


3/39

Sebelumnya Review duluindeks Miller

Pada sebua# sel satuan berbentuk kubus*

(a)barkan bidan( ini+

(a) ,-%-* *

(b) (/--*

(c) ,-%/*

(d) ,---*

,e ,/-/


4/39

WHY STUDYImperfectionsin Solids? Siat ba#an dipen(aru#i 0le# adan1a

ketakse)purnaan atau "a"at

Siat )ekanik l0(a) )urni akan san(at

ban1ak beruba# bila dipadu 1aitu at0)

i)purities dita)b#akan.

C0nt0#+ 2unin(an 7%3 "0pper45%3 6in"

au# lebi# kuat dan keras dibandin(kanden(an te)ba(a )urni.


5/39

Tujuan PembelajaranSetela# )e)pelaari bab ini* 8nda #arus )a)pu+

-. Menelaskan "a"at 'akansi dan "a"at intersisi ./. Men(#itun( persen at0) atau persen )assa dari

)asin( )asin( unsur pen1usun paduan

5. Me)bedakan antara disl0kasi tepi* disl0kasi ulir dan

disl0kasi "a)puran&. Men1ebutkan dua tipe larutan padat dan )enuliskan

atau )e)buat sketsa )asin(9)asin(

:. Mendeskripsikan struktur at0) di daera# (rainb0undar1 dan di sekitar twin b0undar1


6/39

Imperfeci!ns in S!lids

BONDING

+STRUCTURE

+

DEFECTS

PROPERTIES

Is it enough to know bonding and

structure of materials to estimate

their macro properties ?

Defects do have a significant

impact on the properties of

materials


7/39

Caca Krisal

-. Ca"at titik

a. 'akansi

b. intersisi

/. Ca"at (aris ,satu di)ensi

a. disl0kasi tepi

b. disl0kasi ulir". disl0kasi "a)puran

5. Ca"at interasial ,dua di)ensi


8/39



9/39


Atomic Composition

Bonding

Xtal Structure

Microstructure:Materials properties

Thermo-Me

chanical

Process

ing

Addition and manipulation of defects


10/39

3

Vacancies:-vacant atomic sites in a structure.

Vacancydistortionof planes

Self-Interstitials:-"extra" atoms positioned between atomic sites.

self-interstitialdistortion

of planes

P"I#T $%&%CTS 'CacaTiik(


11/39

)umla* vakansi yan+ seimban+unuk sejumla* maerial naik

bila emperaur naik,

Boltmann!s constant

#.3$ x #%-&3'(atom )*

$.+& x #%-,eV(atom )*

= exp

/01

o. of defects

o. of potentialdefect sites.

2ctivation enery

1emperature

4ac5 lattice siteis a potentialvacancy site


12/39

+

6itun 7umla5 va0ansi setimban dalam # m38u pada #%%%%8

i0eta5ui:28u9 +3.,(mol9 $. (cm

3

/V9 %.;eV(atom29 +.%& x #%&3atoms(mole

$.+& x #%-,eV(atom-)

%.;eV(atom

#& 9 228u

x x #m3 9 $.% x #%&$sites

9 &.< ? #%-

2nswer:

9&.< ? #%-? $.% x #%&$sites 9&.&x #%&,vacancies

Memperkirakan k!nsenrasivakansi


13/39

Lai*an-

S0al &.- Callister

itun( raksi at0) 'akansi untuk te)ba(a pada titik

leburn1a ,-5:72. 8su)sikan ener(i untuk

pe)bentukan 'akansi adala# %*%*


14/39

LAR.TA# PA$AT

Larutan padat disusun atas induk atau pelarut (solvent) ataumatriks yang melarutkan sejumlah kecil komponen (terlarut,solute). Kemampuan untuk melarutkan disebut daya larut.

Solvent+ adala# unsur 1an( u)la#n1a lebi# ban1ak Solute+ adala# unsur atau sen1awa 1an( u)la#n1a lebi# sedikit.

Solid Solution, larutan padat+ #0)0(en Struktur kristal )asi# tetap Men(andun( i)purities 1an( terdistribusi se"ara a"ak ,substitusi 0r

intersisi

Second Phase, fasa kedua8pabila at0)9at0)* terlarut dita)ba#kan*sen1awa baru atau struktur baru bisa terbentuk karena )elewatibatas kelarutann1a* atau s0lute )e)bentuk endapan l0kal,didiskusikan pada bab


15/39

K!ndisi yan+ mendukun+erbanuknya laruan pada subsiusi

u)e 4 R0t#er1 rules -. r ,at0)i" radius @ -:3 /. Pr0Ai)it1 in peri0di" table

i.e.* si)ilar ele"tr0ne(ati'ities

5. Sa)e "r1stal stru"ture 0rpure )etals &. =alen"1 eBualit1

8ll else bein( eBual* a )etalwill #a'e a (reater tenden"1

t0 diss0l'e a )etal 0 #i(#er'alen"1 t#an 0ne 0 l0wer'alen"1 ,it pr0'ides )0reele"tr0ns t0 t#e "l0ud


16/39

8ppli"ati0n 0 u)e4R0t#er1 rules 4 S0lid S0luti0ns

-. 0uld 10u predi"t

)0re 8l 0r 8(

t0 diss0l'e in nG

/. M0re n 0r 8lin CuG

Table 0n p. -%H* Callister 7e.

Element Atomic Crystal Electro- Valence

Radius Structure nega-

(nm) tivity

Cu %.-/7? FCC -.< /

C %.%7- %.%&H

O %.%H%

8( %.-&&: FCC -.< -

8l %.-&5- FCC -.: 5

C0 %.-/:5 CP -.? /

Cr %.-/&< JCC -.H 5

Fe %.-/&- JCC -.? /

Ni %.-/&H FCC -.? /

Pd %.-57H FCC /./ /

n %.-55/ CP -.H /

M0re 8l be"ause si6e is "l0ser and 'al. Is

#i(#er 4 but n0t t00 )u"# 4 FCC in CP

Surel1 n sin"e si6e is "l0ser t#us

"ausin( l0wer dist0rti0n ,&3 's -/3


17/39

$

1wo outcomes if impurity B* added to 5ost 2*:

Solid solutionof Bin 2i.e.> random dist. of pointdefects*

Solid solution of Bin 2plus particles of a new p5ase usually for a larer amount of B*

@A

Substitutionalalloye..> 8uin i*

Interstitialalloy

e..> 8in =e*

Second p5ase particle--dierent composition--often dierent structure.

CACAT TITIK PA$A PA$.A#


18/39

#%

eCnition: 'umla5 impurities B* dan loam indu0

2* dalam sistem

D Eassa Dwt solidsolutions*

2da dua cara:

D2tom D atomiclevel*

8B9

mass of B

total massx #%%8!

B9

F atomsof B

total F atomsx #%%

)onversi antara wt D and atD pada paduan 2-B:

8B98!B2B

8!222G8!B2B

x #%% 8!B98B(2B

82(22G8B(2B Basis for conversion:

mass of B9moles of Bx 2B

atomic wei5t of B

mass of 29moles of 2x 22

atomic wei5t of 2

K"MP"SISI


19/39

Lai*an

&.7 #at is t#e "0)p0siti0n* in at0) per"ent* 0an all01 t#at "0nsists 0


20/39

8nd+K slip between "r1stal planes result w#en disl0"ati0ns )0'e*

K t#is )0ti0n pr0du"es per)anent ,plasti" de0r)ati0n.

8re "alled Disl0"ati0ns+

S"#e)ati" 0 in" ,CP+

K be0re de0r)ati0n K ater tensile el0n(ati0n

slip steps w#i"# are

t#e p#1si"al

e'iden"e 0 lar(enu)bers 0

disl0"ati0ns slippin(

al0n( t#e "l0se

pa"ked plane

%%%-

Line $efecs

8dapted r0) Fi(. 7.?* Callister 7e.


21/39

Linear Dee"ts ,Disl0"ati0ns

8re 0ne9di)ensi0nal dee"ts ar0und w#i"# at0)s are)isali(ned

Ed(e disl0"ati0n+ eAtra #al9plane 0 at0)s inserted in a "r1stal stru"ture b (the berger$s vector) is ,perpendi"ular t0 disl0"ati0n

line S"rew disl0"ati0n+

spiral planar ra)p resultin( r0) s#ear de0r)ati0n bis ||,parallel t0 disl0"ati0n line

%urger$s vector, bis a measure of lattice distortion and is

measured as a distance along the close packed directions in

the lattice


22/39

%d+e $isl!cai!n

Fi(. &.5* Callister 7e.

Ed(e Disl0"ati0n


23/39

K Disl0"ati0n )0ti0n reBuires t#e su""essi'e bu)pin(

0 a #al plane 0 at0)s ,r0) let t0 ri(#t #ere.

K J0nds a"r0ss t#e slippin( planes are broken and

remadein su""essi0n.

8t0)i" 'iew 0 ed(e

disl0"ati0n )0ti0n r0)

let t0 ri(#t as a "r1stalis s#eared.

,C0urtes1 P.M. 8nders0n

M!i!n !f %d+e $isl!cai!n

#ttp+!!www.wile1."0)

!"0lle(e!"allister!C

L$EST%-%5-$S!')se!

disl0"ati0ns.#t)
http://www.wiley.com/college/callister/CL_EWSTU01031_S/vmse/dislocations.htmhttp://www.wiley.com/college/callister/CL_EWSTU01031_S/vmse/dislocations.htmhttp://www.wiley.com/college/callister/CL_EWSTU01031_S/vmse/dislocations.htmhttp://www.wiley.com/college/callister/CL_EWSTU01031_S/vmse/dislocations.htmhttp://www.wiley.com/college/callister/CL_EWSTU01031_S/vmse/dislocations.htmhttp://www.wiley.com/college/callister/CL_EWSTU01031_S/vmse/dislocations.htmhttp://www.wiley.com/college/callister/CL_EWSTU01031_S/vmse/dislocations.htmhttp://www.wiley.com/college/callister/CL_EWSTU01031_S/vmse/dislocations.htm


24/39

Issue a /and

BASIC THINKING:The energy required deform a

crystal in the manner described

above will require the breaking all

of the bonds on one plane of

atoms !However, measured forces required

to induce similar deformations in

single crystals were much lower.

How come ?

DIS!CATI!"S #The e$planation came in %&'( )hen !ro)an*

Polan+i* and Ta+lor postulated the e$istence

of dislocations, in cr+stal structures

Dislocations can .e /isuali0ed as an e$tra

lattice planes inserted in the cr+stal* .ut note$tending through all of the cr+stal .ut

ending in the dislocation line 12A3 -

PA"45

Dislocation motion allo)s for the slip 6

plastic deformation- of cr+stals

,7olterra and .+ Timpe in %&88s #


25/39

0erakan disl!kasi

Slip Plane

DIS!CATI!" C!94:

Induces a stress field due to local

distortions in the structure


26/39

$ISL"CATI"#S

Bahan akan mengalami deformasi (perubahan bentuk) yang

permanen sejalan dengan berpindahnya dislokasi melalui

kristal. Ikatan patah dan terbentuk kembali tetapi hanya

sepanjang garis dislokasi pada semua titik pada saat tertentu,bukan seluruh bidang.


27/39

$isl!cai!n M!i!n

Disl0"ati0n )0ti0n is anal0(0us t0 )0'e)ent0 a "aterpillar+

T#e "aterpillar instead 0 spendin( a l0t 0 ener(1t0 )0'e its entire b0d1 at 0n"e* )0'es its 0rwarda bit and "reates a hump, ie a disl0"ati0n T#ehump t#en pr0pa(ates al0n( t#e "aterpillar and

)0'es t#e "aterpillar b1 a s)all a)0unt.


28/39

Screw $isl!cai!ns

8dapted r0) Fi(. &.&* Callister 7e.

Jur(ers 'e"t0r b

Disl0"ati0n

line

b

,a

,b
http://www.wiley.com/college/callister/CL_EWSTU01031_S/vmse/dislocations.htm


29/39

%d+e1 Screw1 and Mi2ed$isl!cai!ns

8dapted r0) Fi(. &.:* Callister 7e.

Ed(e

S"rew

MiAed


30/39

Disl0"ati0ns are 'isible in ,T ele"tr0n )i"r0(rap#s

8dapted r0) Fi(. &.H* Callister 7e.


31/39

$isl!cai!ns and Maerials

Sren+* FCC )etals are in (eneral )0re du"tile;plasti"all1 de0r) well be0re ailure

CP )etals are in (eneral less du"tile

JCC )etals are str0n(er due t0 interse"tin(

slip planes; li)ited disl0"ati0n a"ti'it1; w0rk

#arden 'er1 Bui"kl1


32/39

$isl!cai!ns 3 Crysal Srucures

K Stru"ture+ "l0se9pa"ked

planes dire"ti0ns are preerred.

'iew 0nt0 tw0

"l0se9pa"ked

planes.

"l0se9pa"ked plane ,b0tt0) "l0se9pa"ked plane ,t0p

"l0se9pa"ked dire"ti0ns

K C0)paris0n a)0n( "r1stal stru"tures+ FCC+ )an1 "l0se9pa"ked planes!dire"ti0ns;

CP+ 0nl1 0ne plane* 5 dire"ti0ns;

JCC+ n0ne super9"l0se )an1 near "l0se

K Spe"i)ens t#atwere tensile

tested.

M( ,CP

8l ,FCC

tensile dire"ti0n


33/39

Planar $efecs in S!lids

One "ase is a twin b0undar1 ,plane Essentiall1 a rele"ti0n 0 at0) p0siti0ns a"r0ss t#e twinnin( plane.

Sta"kin( aults F0r FCC )etals an err0r in 8JC8JC pa"kin( seBuen"e EA+ 8JC8J8JC

8dapted r0) Fi(. &.


34/39

S0lidii"ati0n9 result 0 "astin( 0 )0lten )aterial / steps

Nu"lei 0r)

Nu"lei (r0w t0 0r) "r1stals 4 (rain stru"ture

Start wit# a )0lten )aterial 4 all liBuid

8dapted r0) Fi(.&.-& ,b* Callister 7e.

Cr1stals (r0w until t#e1 )eet ea"# 0t#er

nu"lei "r1stals (r0win( (rain stru"tureliBuid


35/39

P!lycrysalline Maerials

Qrain J0undaries re(i0ns between "r1stals

transiti0n r0) latti"e 0 0ne

re(i0n t0 t#at 0 t#e 0t#er

sli(#tl1 dis0rdered

l0w densit1 in (rain

b0undaries

#i(# )0bilit1

#i(# diusi'it1 #i(# "#e)i"al rea"ti'it1

8dapted r0) Fi(. &.7* Callister 7e.


36/39

#,

Hrain boundaries:

are boundaries between crystals. are produced by t5e solidiCcation process> forexample. 5ave a c5ane in crystal orientation across t5em. impede dislocation motion.

rainboundaries

5eat

Iow

Sc5ematic

2dapted from =i. . Callister 6e.2dapted from =i. .#%> Callister

6e. =i. .#% is from Metals Handbook> Vol. ;> ;t5edition> Metallography and Microstructures> 2m.

Society for Eetals> Eetals Jar0> @6> #;$,.*

K $cmEetal Inot

AR%A $%&%CTS- 0RAI#4".#$ARI%S


37/39

Micr!sc!pic %2aminai!n

Cr1stallites ,(rains and (rain b0undaries. =ar1

"0nsiderabl1 in si6e. Can be Buite lar(e eA+ Lar(e sin(le "r1stal 0 Buart6 0r dia)0nd 0r Si

eA+ 8lu)inu) li(#t p0st 0r (arba(e "an 9 see t#e

indi'idual (rains

Cr1stallites ,(rains "an be Buite s)all ,)) 0r

less 4 ne"essar1 t0 0bser'e wit# a )i"r0s"0pe.


38/39

K seul up t0 /%%% )a(nii"ati0n.

K P0lis#in( re)0'es sura"e eatures ,e.(.* s"rat"#esK Et"#in( "#an(es rele"tan"e* dependin( 0n "r1stal

0rientati0n.

Mi"r0(rap# 0

brass ,a Cu9n all01

%.7:))

"pical Micr!sc!py

8dapted r0) Fi(. &.-5,b and ,"* Callister

7e. ,Fi(. &.-5," is "0urtes1

0 .E. Jurke* Qeneral Ele"tri" C0.

"r1stall0(rap#i" planes


39/39

K P0int* Line* and8readee"ts eAist in s0lids.

K T#e nu)ber and t1pe 0 dee"ts "an be 'aried

and "0ntr0lled ,e.(.* "0ntr0ls 'a"an"1 "0n".

K Dee"ts ae"t )aterial pr0perties ,e.(.* (rain b0undaries "0ntr0l "r1stal slip.

K Dee"ts )a1 be desirable 0r undesirable ,e.(.* disl0"ati0ns )a1 be (00d 0r bad* dependin(

0n w#et#er plasti" de0r)ati0n is desirable 0r n0t.

Summary

bab 4_cacat kristal

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