plymouth materials characterisation project celebratory launch … · 2018-03-08 · •grain size...

The Business of Science®

© Oxford Instruments 2014 CONFIDENTIAL

What is EBSD?

What can it do for you?

Plymouth Materials Characterisation Project Celebratory Launch



• EBSD – Electron BackScattered Diffraction

• Your eye into crystal structures

• Most engineering & geological materials are crystalline with

macro/micro/nanostructure

• EBSD gives quantitative macro/micro/nanostructure

• Produces information similar to X-Ray diffraction, TEM

• Use it to develop new materials, control material properties,

manufacturing processes and investigate failures, corrosion etc.

• High complimentary to EDS chemical analysis

• New AZtec ‘Symmetry’ CMOS EBSD detector – super sensitive,

3000Hz max

Introduction to EBSD



Typical Measurements •Grain size

•Global texture

•Local texture

•Recrystallised / deformed fractions

•Substructure analysis

•Strain analysis

•Grain boundary characterisation

•CSL boundary distribution

•Phase identification

•Phase distribution

•Phase transformations

•Fracture & failure analysis ...

Industries •Academia, Research, R&D

•Metals production & processing

•Aerospace

•Nuclear

•Government & defence

•Petrochemical and chemical

•Automotive

•Microelectronics

•Power Generation and

distribution

•Earth sciences ...

EBSD Applications

Materials •Metals, Alloys,

•Intermetallics

•Ceramics

•Thin films

•Geological minerals

•Semiconductors

•Superconductors ...

See the dedicated EBSD website: http://www.EBSD.com



• ...Diverse materials, production methods

and uses...

• Cast products

• Wrought products

• Many metalworking processes have

been developed; casting, forging, rolling,

extrusion, sintering, cladding, plating,

joining, thermal spraying, surface

treatments etc., extremely diverse

methods for metal production, machining

and fabrication have been developed,

with macro/micro and nanostructure

being key to material performance

• Materials may be polycrystalline, or for

special uses single crystal – the need to

tailor properties or formability for specific

or extreme applications is now

commonplace

• X-Ray diffraction, microscopy and EDS

have been used to characterise

materials, but EBSD is increasingly the

‘go to technique’ being both powerful and

convenient to use on an SEM,

particularly in conjunction with EDS

Introduction to metallurgy and materials

http://www.google.co.uk/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwjmmK6qrY_ZAhXlJMAKHSNUB3oQjRwIBw&url=http://www.sfpathway.com/markets/power-generation/nuclear-power-plants/&psig=AOvVaw2imO9PXINOw3tUDVkYjkDM&ust=1517939941529960

https://www.google.co.uk/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwi9hJLvro_ZAhXMDMAKHWnhCkQQjRwIBw&url=https://www.quora.com/Is-flying-on-an-airliner-safe&psig=AOvVaw0QtaIbvdYAmRMvovWeRALW&ust=1517940340056147

http://www.google.co.uk/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwjIqJCHro_ZAhWLAcAKHYuWBpEQjRwIBw&url=http://nationalinterest.org/blog/the-buzz/why-americas-nuclear-submarines-would-crush-russia-or-china-20477&psig=AOvVaw1q-6XeFPmr77hhMZ1vjajw&ust=1517940131922998



• Cast structures

Casting

https://www.google.co.uk/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=2ahUKEwjMzJTP747ZAhXHDMAKHQ6xAr4QjRx6BAgAEAY&url=https://www.tf.uni-kiel.de/matwis/amat/iss/kap_6/illustr/s6_2_1c.html&psig=AOvVaw0zNIzKt08RkIYIeoTNklM-&ust=1517923436594836

http://www.google.co.uk/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=2ahUKEwj68pDL8I7ZAhUlJMAKHRmfAKUQjRx6BAgAEAY&url=http://www.georgesbasement.com/Microstructures/NonFerrousAlloys/Lesson-1/Specimen05.htm&psig=AOvVaw0zNIzKt08RkIYIeoTNklM-&ust=1517923436594836

https://www.google.co.uk/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=2ahUKEwiJwLir8Y7ZAhXMCcAKHT-gBNAQjRx6BAgAEAY&url=https://commons.wikimedia.org/wiki/File:Cast_ingot_macrostructure.svg&psig=AOvVaw1UeMeaU-_O_VVzhxgk9OTL&ust=1517923824437543



• 1781 Iron Bridge

Shropshire (left)

• Aldford bridge

Cast Iron



• Cast iron strong in

compression but

weak in tension or

bending

• Cracking and brittle

failures common

• Wrought products

offer better

properties for many

applications

Limitations of cast iron

//upload.wikimedia.org/wikipedia/commons/5/5c/Bridge_defect1.jpg

//upload.wikimedia.org/wikipedia/commons/2/29/Ironbridge2.jpg



• Casting good for forming

Large/small/intricate

shapes

• Directional solidification

and cooling dynamics

can create highly

ordered or single crystal

structures

Cast products



• Breaks down cast

structure

• Hot or cold rolled

• A = hot rolled, ‘black’

product – microstructure

subject to ‘recovery’

• B = cold rolled, ‘bright’

better accuracy and finish

with deformed

microstructure

• Sheet, rod, bar, tube and

shapes can be

economically formed by

rolling, forging and other

deformation processes

Wrought product

Courtesy Mount Druitt Mechanical Engineering



• Rolled structures

• Cast structure

obliterated and new

structure developed

• Crystallographic ‘texture’

may be devloped

Wrought product

Rolled thread

https://www.google.co.uk/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=2ahUKEwjV7uv0847ZAhXDBsAKHY4gCHMQjRx6BAgAEAY&url=https://www.researchgate.net/figure/258298918_Figure-1-Cold-rolled-50-ferrite-pearlite-microstructure-with-5-pearlite-black-pearlite&psig=AOvVaw3N2GDnTY8dSdv4EkGFPK42&ust=1517924577174992



• Forming characteristics –

formability

• Sheet, forgings, extrusions

• Strength

• Material properties...

• ...whether cast,

wrought/other – the

importance of crystal

structure and


is key to properties

• EBSD delivers quantitative


analysis

Wrought product

https://www.google.co.uk/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=2ahUKEwj3rrDugY_ZAhVLCMAKHQy8BUEQjRx6BAgAEAY&url=https://shanghaimetalcorporation.wordpress.com/2014/09/25/a-potential-solution-to-the-body-car-impasse/&psig=AOvVaw090CQ8MSRELQcK4mgLI_Ow&ust=1517928220917667

https://www.google.co.uk/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=2ahUKEwieiMGog4_ZAhXKJcAKHevGCt4QjRx6BAgAEAY&url=https://www.pinterest.com/pin/468022586249067092/&psig=AOvVaw3W6UuKU1a3ht0GOVkj2OQv&ust=1517928661905072

https://www.google.co.uk/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=2ahUKEwjBmLewiI_ZAhULKcAKHYXeAWoQjRx6BAgAEAY&url=https://www.baesystems.com/en/product/typhoon&psig=AOvVaw1sBnnBHRl-ma82XGXaU96Q&ust=1517930043840410



Crystal structure - The Atomium, Brussels

• Body

Centred

Cubic

(BCC)

unit cell

for Iron

• Magnified

165 Billion

times



Crystal structure

• Body

Centred

Cubic

(BCC)

unit cell

for Iron

• Magnified

165 Billion

times

• Ordered

‘arrays’ or

rafts of

unit

cells...



Introduction to EBSD – Crystal structure

• A model of a simple

cubic crystal structure

(NaCl) magnified

~1Billion times

• This model strikingly

demonstrates the

atomic arrangement of

‘planes’

• EBSD allows the

planes to be visualised

at more modest

magnification in the

SEM by electron

diffraction

• EBSD gives an

incredible insight into

microstructure and

material properties Acknowledgement: Dr Rober Krickl



• Close up of

crystal

model

showing

‘planes’ and

intersections





• Close up of

crystal

model

showing

‘planes’ and

intersections

As previously, converted to monochrome and blurred in

‘Photoshop’




As previously, converted to monochrome and blurred in

‘Photoshop’

• Close up of

crystal

model

showing

‘planes’ and

intersections




• Actual

diffraction

pattern

showing that

EBSD allows

you to see

into the

crystal

structure –

• Planes in

Crystal =

bands in

pattern



Introduction to EBSD – band detection

• A number of

bands are

detected

using

advanced

computer

algorithms



Introduction to EBSD - indexing

• The bands

are

compared

with known

crystal

structures

such that

different

crystal types

and

orientations

can be

displayed...

An ‘overlay’ of the solution is shown over the diffraction

pattern for visual confirmation of the result



• During mapping

the beam is

scanned across

the sample in a

raster

• As the beam falls

on different

crystal structure

i.e. grains and or

phases, EBSPs

relating to that

point are

recorded on the

phosphor



From Pattern to maps & measures

• Crystal Orientation Maps

• Show crystal orientations

• Grain size & boundaries

• Phases

• Strain

• Orientation obtained at every pixel in map

• Colour derived from colour key

• Up to 3000 measurements/sec with AZtec

‘Symmetry’


Colour

key



Phase Area Fraction & Distribution

Duplex Steel




copper

• Isolate

grains by

strain

Analysis of strain




Strain (grain average misorientation) distribution map

Strain (grain average misorientation) classification map

Red = deformed

Blue = Recrystallized

Segmenting data by strain state - Recrystallisation

Rolled Mo Sheet




Rolling & heat

treatment of Fe-Al

binary alloy resulted

in a partly deformed,

partly recrystallized

microstructure

Grains subgrouped

by residual strain

state:

Red deformed,

blue recrystalllized

Recrystallized

Deformed

Texture ‘partitioning’

revealed

Segmenting data by strain state - Recrystallisation




Each orientation is surrounded by 8 nearest neighbors. The

disorientation is calculated through all of the 8 nearest

neighbors to get an averaged value. gij = gi gj-1

Disorientation angle (degrees)

Visualisation of strain




• Sintered

Nickel for

aerospace

application

Cracking in Sintered Nickel




• Sintered

Nickel for

aerospace

application

• Orientation

map




• Sintered

Nickel for

aerospace

application

• ‘Kernel

Average

Misorientation

(KAM)

• Strain

associated

with crack




• Sintered

Nickel for

aerospace

application

• Disorientation

colouring

• Showing

strain fields



Strain localization + GB map

Ta sputter target

Semiconductor – sputter target




Joining

• A ‘Large Area Map’ (LAM) collected over the sample area of 7.5mm x 2mm

• 132 individual fields, montaged together and analysed as a single data set

• The orientation map illustrated the change in microstructure through the heat affected zone (HAZ)

• There is a columnar structure in the melted region

• With EBSD it is possible to characterise the change in microstructure through the weld.

• Grain size, shape and orientation revealed

• Spot Weld Characterisation



Non-preheated Preheated

Phase maps (+ GBs): red = ferrite, blue = austenite

Joining: Phase distribution & texture in laser welded duplex steel




Heat treatment of deformed material

• Grain size and deformation distribution studied in a folded steel sheet

Prior to annealing After annealing at 600° • Comparison of grain size before and after annealing

• Grain size and Grain Orientation Spread average values as function of the distance across the sample



Complex Component Analysis – Spark Plug

• Examine the interface between copper and nickel in the centre of the plug • EBSD gives detail on the phase location, grain size and grain boundary

characterisation:



• Copper/nickel interface in the centre of the plug • Grain orientation information, and preferred orientation





• Investigation of the thread root in steel casing • IPF map shows the texture in the thread in the steel



The proportions of

phases impact on how

the steel will behave in

different regimes. How to

discriminate martensite,

bainite and ferrite phases

in steel?

EBSD discriminates

these three phases

based on pattern

quality.

The results are phase

identification, phase

quantification.

???

Discriminate Martensite & Bainite in steel



• Transformation Induced Plasticity (TRIP) Steel was mainly developed for

automotive applications as they possess high strength, good ductility

ratios, formability and energy absorption properties.

• They have a complex multiphase microstructure containing retained

austenite, martensite, ferrite and bainite.

Discriminate Martensite & Bainite in steel

Phase map and phase fraction

show results

Band Contrast Phase Map

• Using this technique we can reliably differentiate the phases in a four phase

TRIP steel



Material texture analysis: Titanium & Magnesium

• Titanium and its alloys are

applied in a range of applications

in aerospace component, owning

to their high corrosion resistance

and strength.

• Magnesium and its alloys are the

lightest structural metallic

materials and so are used in

many weight saving applications

in modern cars

Understanding and controlling

texture is key for implementing

magnesium.

Orientation map of a Ti alloy

(0001) texture

Orientation map of a Mg alloy

(0001) texture



Material texture analysis: Aluminium

• Alumium alloys are extensively used in engineering structures and

components where light weight and/or corrosion resistance is required in

automotive and areospace industry:

• Adequate fomability is a requirement to produce complex shapes

economically

• Crystallographic texture strongly influences formability

Orientation map of an Al alloy

Goss texture

plymouth materials characterisation project celebratory launch … · 2018-03-08 · •grain size...

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