GholiniaEBSDOverview

8/14/2019 GholiniaEBSDOverview

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Electron Back-Scatter Diffraction in

the Scanning Electron Microscope:

An Overview


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What is EBSD?

Historical Perspective

Crystallography & pattern formation

Data Collection

Recent Developments Conclusions

al! "utline


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What is EBSD?

EBSD # electron $ac!scatter %iffraction

SE $ase% techni'ue to measure crystal

orientations

(pplica$le to any crystalline material )in theory*

Provi%es the a$solute crystal orientation +ith su$#

micron resolution

( useful tool for %iscriminating $et+een phases


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EBSD or EBSP?

EBSD# electron $ac!scatter %iffraction

EBSP, electron $ac!scatter %iffraction pattern

BKD, Bac!scattere% -i!uchi Diffraction

And some commercial names....

(C)OM, )Crystal* "rientation apping

ACOM, (utomate% Crystal "rientation

apping OIM. # "rientation /maging icroscopy


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What is EBSD?

Historical Perspective


Data Collection

Recent Developments Conclusions

al! "utline


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EBSD History ,Early Wor!

EBSP li!e patterns +erefirst o$serve% $y-i!uchi )0123* in theransmission Electronicroscope )E*4

5on Boersch )0167*e8ten%e% -i!uchi9s+or!

Mica


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EBSD History ,

(lam et al4 (lam: Blac!man an%

Pashley )01;: -/:

aCl: P$S2

crystals4

Lead Sulphide


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EBSD History , the $irth of

mo%ern EBSD 5ena$les an% Harlan%

)0172* o$serve% EBSPs inthe Scanning Electronicroscope )SE* $y usinga 6@mm %iameter fluorescentimaging screen an% a close%circuit television camera4

Dingley )later 013@s*%evelope% the com$ination

of phosphor an% televisioncamera: an% com$ine% them+ith a graphical overlay4

EBSP from Dingley'sgroup note

calibration marks


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EBSD History , continue%

e8periments in the 013@s Commercial soft+are

)0131* +as %evelope%

to analyse ElectronChanneling Patterns)ECP* an% EBSPs4

E film for high'uality EBSPs & phase

i%entification )013@s*

EBSP from a superalloy collected with EM film


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EBSD History , commercial

systems in the 011@s (utomatic metho%s for

in%e8ing EBSPs)011@s* an% control of

SEs gave rise tomapping an% phase%iscrimination4

Digital cameras: EDA%ata an% phase%ata$ases provi%einformation for phasei%entification )0111 # * Phase map from

duple steel


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EBSD History , the present %ay

High spee% mapping$ecomes a reality

DualCross $eam

system )Electron /on$eam* for 6Dmicroscopy

Com$ine% chemical an%crystallographicmapping

!rientation map of "i#superalloy$ collected at

%& points ( sec


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EBSD set up


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Resulting %iffraction pattern

)EBSP*


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EBSD

Performance

Spatial resolution %o+n to 0@s of nm

Max sample size SE %epen%ent )typically

up to 0@@ 8 ;@mm*Angular resolution @42;#0 at present

Probe current F@42; n(

Accelerating voltage F; !5

Specimen tilt G@#7;

Working distance 0@#


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What is EBSD?


Data Collection

Recent Developments

Conclusions

al! "utline


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EBSP symmetry comes from lattice symmetry

, Crystal system: =aue group: space group

o $uil% a crystal

, Start +ith unit cell

, (%% a $asis

, Repeat a% infinitum444

uv+I is a crystal %irection:

Juv+F is a family of %irections

)h!l* is a crystal plane:

Kh!lLis a family of planes4

EBSP crystallography


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EBSP formation

Spherical

-i!uchi map

Phosphor

Electron $eam stri!esspecimen

Scattering pro%uceselectrons travelling in all%irections

Electrons that satisfy theBragg con%ition

)nM2%4sin* for a plane)h!l* are channele% -i!uchi $an%s

Electrons stri!e thephosphor an% pro%uce light

Which is %etecte% $y a CCDcamera an% %igitise%

he resulting EBSP isautomatically analyse% an%in%e8e%444

/ron unit cell


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(lthough EBSPs are create% $y

$ac!scattere% electrons: the signal

%oes not come from the +hole BSE

interaction volume

/nstea%: the %iffraction signal

effectively originates from a Npoint

sourceN in the top fe+ nm

his means that the EBSD

techni'ue can o$tain very high

resolutions )J2@nm*

EBSD Resolution


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Copper interconnect test

sample (nalyse% on the =E" Supra

;;5P

Resolution E8ample 0

Twin domain !"#$" nm

wide a%e clea%ly

%eol&ed 'ing a nm

te i*e


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Pt thin film

(nalyse% on the OE"=G;@@>

Resolution E8ample 2

+%ain with a mean

diamete% o, -nm a%e

clea%ly %eol&ed 'ing a

nm te i*e

=0.08 m; BC; Step=0.005 m; Grid55x49

=0.08 m; GB+tri-x; Step=0.005 m; Grid55x49


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{100}

[100] [010]

[011]

[001]

{110}(011)

!"

[100]

[001]

[111]

[101]

[201]

[311]

[210]

[011]

[110][010]

Bo%y centre% cu$ic /ron

/ron EBSPJ000F is central

ote J000F has 6

fol% symmetry: $ut is

close to G fol%4

{#00}


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$cc

fcc

82


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Differences in interplanarangles allo+ similar

loo!ing EBSPs from$cc

an% fcc/ron to $e

%istinguishe%4

$cc /ron fcc /ron

$cc /ron fcc /ron

Phase %iscrimination


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What is EBSD?

Crystallography & in%e8ing

Data Collection

Recent Developments

Conclusions

al! "utline


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A ingle a'tomated EBSD %'n %o&ide a

completecha%acte%iation o, the mic%ot%'ct'%e2

Phase %istri$ution

e8ture strength

Qrain sie

Boun%ary properties

isorientation %ata

Slip system activity

/ntra#granular %eformation Plus much: much more

all provided !ile you get on it! somet!ing else..."


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3o%ked e0amle o, a'tomated

EBSD(nalysis of polycrystalline samples of halite

)aCl , cu$ic*

Some samples have $een e8perimentally%eforme%

5ariations in grain sie an% in e8tent of

su$grain %evelopment necessitate analysis at

%ifferent scales

#ata source: $trec!t $niversity% using a P!ilips &'() *+,


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Stage can

o%ientation ma o,

olyc%ytallinehalite

0@@0@@ gri%: step 0@@ m4

< mm

(nalysis time


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;@@ m

6@@6@@ gri%: ; m step

Beam can o%ientation

ma o, olyc%ytallinehalite

(nalysis time 6G minutes


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Stage scan: 6;@6@@ gri%: 2;m spacing

64; mm

Compression

/a%ge a%ea can

o, olyc%ytalline

halite

EBSD on di,,e%ent cale I


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2@@ m2@@ m

A

B

Beam scan: 2;@2;@ gri%: 24; m spacing

-ieing intragrain microstructure and local lattice orientation variations...

Reflecte% light image

EBSD on di,,e%ent cale II


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@

0

2

6

/B an% electron $eam*


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EBSD %etectors

=o+ light EBSP camera, Silicon intensifie% target )S/*

3 $it: very noisy

, CCD , 5 type vi%eo signal3 $it less noisy

, Slo+ scan CCD02 $it: lo+ noise: high spee%: $inning

Binning /ncreases signal: re%uces noise

Higher spee% $ut at lo+er resolution


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EBSPs # >el%spar

"l% Camera e+ Camera


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Halite # aCl

020:2@< points


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6D#EBSD


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What is EBSD?

Crystallography & in%e8ing

Data Collection

Recent Developments

Conclusions

al! "utline


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Conclusions

EBSD is an SE#$ase% techni'ue that has $een

!no+n for ;@ years: $ut only +i%ely applie% in the

last 0@ years

EBSD is no+ a fast: automate% techni'ue:applica$le to most crystalline materials

EBSD provi%es phase i%entification: te8ture an%

$oun%ary characteristics44444

Documents

GholiniaEBSDOverview