Origins of AGG in FSW 5083 - Li Group...

Origins of AGG in FSW 5083 1Wagoner & Chen

Origins of AGG in FSW 5083

Project Summary

Robert H. Wagoner, ProfessorKe Chen, Graduate Research Associate

Department of Materials Science and EngineeringThe Ohio State University

March 1, 2007


• New OSU Results

• New SNU Results

• Unchanged OSU Results

Organization


• Grain size and second phase particles

• Misorientation angle

• Elevated Temperature Tensile Test

New OSU Results


• Magnification on the OIM was wrong, therefore the grain sizes were not correctly measured

• The step size and scan area were made consistent at 0.2 and 50*50μm2 respectively for comparison

• Expected phases were entered in OIM to resolve particles – Al, MnAl6 (or FeAl6), (CrFe)Al7, Mg2Al3, SiMg2, and Al2O3

Corrections Since Oct 2006


1000, 100

1000, 150

1000, 200

1000, 300

1500, 150

1500, 225

1500, 300

1500, 450

[rpm], [mm/min]

RotationalSpeed

Travel Speed

As received

1 minute at 870F

2.5 minute

5 minute

10 minute

20 minute

1 hour

2 hours

1000rpm*100mm/min

Grain Morphologies after Heat Treatment

AGG vs. Weld Condition AGG vs. Time


Heat Input Plot

800

1000

1200

1400

1600

1800

0 100 200 300 400 500Travel Speed (mm/min)

Rot

atio

nal S

peed

(rpm

)

Heat Input

High

Low

Most AGG

Least AGG

Optimized


Sample Overview

Least AGG

Most AGG

Optimized Condition

• Heating at 465 ℃ for 5 min


Least AGG Condition

1A_T (TOP, AGG)

Step Size: 1μm

G.S. ~ 5000μm2

G.S. ~ 3.2μm2

Non-AGGed Region

AGGed Region


Conversion between Area of Average Grain and Spherical Grain Size

• Area of Average Grain is designated Aavg

• Intercept width of a circular grain section: lavg = (π*Aavg/4)0.5

• Two ways to convert the Intercept width to volumetric (spatial) diameter

– Assume grains are similar size spheres: Davg = 1.5*lavg

– Assume grains are tetrakaidecahedron-shaped: Davg = 1.571*lavg


Data Summary Form


Phase Map Table

Least AGG Most AGG Optimized

1B_M (MID) 3B_M (MID)AGG

2B_T (TOP) AGG

2B_M (MID)Non-AGG Non-AGG

3B_T (TOP) AGG1B_T (TOP) AGG


Step Size: 0.2μmAA5083-H18 Base Material AA5083-O Base MaterialG.S. > 3.68μm2 G.S. = 7.28μm2

Phase Maps


Least AGG Condition

Step Size: 0.2μm1B_T (TOP, AGG) 1B_M (MID, NO-AGG)G.S. = 4.54μm2G.S. = 2.66μm2


Most AGG Condition

Step Size: 0.2μm 2B_M (MID, AGG)2B_T (TOP, AGG)G.S. = 1.94μm2 G.S. = 3.23μm2


3B_T (TOP, AGG)

Optimized Condition

Step Size: 0.2μm 3B_M (MID, NO-AGG)G.S. = 4.07μm2G.S. = 2.28μm2


Optimized Condition

Step Size: 0.2μm 3A_M (MID, NO-AGG)G.S. = 4.19μm2G.S. = 4.07μm2

3B_M (MID, NO-AGG)


Comparison Between Most AGG Site and Least AGG Site

2B_M (MID, AGG) 1B_M (MID, NO-AGG)

Most AGG Least AGG

G.S. = 3.28μm2 G.S. = 4.54μm2


Optimized Condition

Step Size: 0.2μm

3A_M (MID, NO-AGG)G.S. = 4.19μm2

3A_Top (TOP, AGG)

Step Size: 0.05μm

G.S. = 0.38μm2

G.S. ~ 5000μm2

Very close to top surface

AGGed Region


0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 6.5 7 7.5 8 8.5 9 9.5 10

Gra in P lana r Dia me te r (mic ron)

Grain Size DistributionLeast AGG Condition

Avg GS (μm2)

1B_T(TOP AGG)

2.66

1B_M(MID Non-AGG)

4.54


0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.5 1.5 2.5 3.5 4.5 5.5 6.5 7.5 8.5 9.5

Grain Planar Diameter (micron)

Num

ber F

ract

ion

Most AGG Condition

Avg GS (μm2)

2B_T(TOP AGG)

1.94

2B_M(MID AGG)

3.23


0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.5 1.5 2.5 3.5 4.5 5.5 6.5 7.5 8.5 9.5

Grain Planar Diameter (Micron)

Num

ber F

ract

ion

Optimized Condition

Avg GS (μm2)

3B_T(TOP AGG)

2.28

3B_M(MID Non-AGG)

4.07


Boundary Misorientation Angle

0

1

2

3

4

0 10 20 30 40 50 60 70Misorientation (o)

Freq

uenc

y (%

)

The mean boundary misorientation would be 40.5o (Mackenzie, 1985)

Misorientation Distribution for a Randomly Oriented Assembly of Grains


Optimized Condition

3B_T (TOP) 3B_M (MIDDLE)

With boundaries between identified grainsOnly grain boundaries which have misorientation > 5o will be counted in

Mean = 34.96° Mean = 37.69°


Most AGG Condition

2B_M (MIDDLE)2B_T (TOP, AGG)


Mean = 35.82° Mean = 37.92°


Least AGG Condition

1B_T (TOP) 1B_M (MIDDLE)


Mean = 34.12° Mean = 37.28°


Stress vs. Strain, Strain Rate, and Temperature

• AA5083-H18• AA5083-O• AZ31 Mg


5083 H18 at True Strain Rate=10^(-1)/s

050

100150200250300350400450500

0 0.1 0.2 0.3 0.4 0.5 0.6

True Strain

True

Str

ess

(MP

a) RT100C200C300C400C

5083-H18 at True Strain Rate=10^(-2.5)/s

0

50

100

150

200

250

300

350

400

450

500

0 0.1 0.2 0.3 0.4 0.5 0.6

True Strain

RT100C200C300C400C

AA5083-H18

5083-H18 at True Strain Rate=10^(-4)/s

050

100150200250300350400450500

0 0.1 0.2 0.3 0.4 0.5 0.6

True Strain

True

Str

ess

(MP

a)

RT100C200C300C


AA5083-O

5083O at True Strain Rate=10^(-1)/s

050

100150200250300350400450500

0 0.1 0.2 0.3 0.4 0.5 0.6

True Strain

True

Stre

ss (M

Pa)

RT100C200C300C400C

5083O at True Strain Rate=10^(-2.5)/s

050

100150200250300350400450500

0 0.1 0.2 0.3 0.4 0.5 0.6

True Strain

True

Stre

ss (M

Pa)

RT100C200C300C400C

5083_O at True Strain Rate=10^(-4)/s

050

100150200250300350400450500

0 0.1 0.2 0.3 0.4 0.5 0.6

True Strain

True

Stre

ss (M

Pa)

RT100C200C300C


AZ31 Mg

AZ31B at True Strain Rate=10^(-1)/s

050

100150200250300350400450500

0 0.1 0.2 0.3 0.4 0.5 0.6

True Strain

True

Str

ess

(MPa

)

RT100C200C300C400C

AZ31B at Strain Rate=10^(-2.5)/s

050

100150200250300350400450500

0 0.1 0.2 0.3 0.4 0.5 0.6

True Strain

True

Stre

ss (M

Pa)

RT100C200C300C400C

AZ31B at True Strain Rate=10^(-4)/s

050

100150200250300350400450500

0 0.1 0.2 0.3 0.4 0.5 0.6

True Strain

True

Tre

ss (M

Pa)

RT100C200C300C


Conclusions

• Abnormal grain growth rate is affected by more than one factor: grain size, dislocation content, grain boundary misorientation, grain size distribution, and particle fraction

• Regions close to the top surface with small grains and relatively higher dislocation density promote AGG

• FSW regions are not well recrystallized. They are either textured or deformed

• Higher angle grain boundaries favor grain growth


Future Work

• With the data from SNU, find the FSW Temp- Time correlation

• Use EDAX in TEM to find the intermetallic phases

• Analyze the grain size distribution


New SNU Results


ResultsTemperature History (sensor) : AA5083-H18

Advancing side Retreating side

Experiment 525 420 300 480 400 300

Experiment 460 400 205 ∙ ∙ ∙

Experiment 530 450 262 ∙ ∙ ∙

Property 1 535 462 302 534 438 288

Property 2 514 494 328 511 474 315

1000rpm & 100mm/min

1000rpm & 300mm/min

1500rpm & 150mm/min

2mm 5mm 8mm 2mm 5mm 8mm

Property 1 496 426 253 491 399 240

Property 2 470 440 261 465 412 248

Property 1 569 506 320 568 474 303

Property 2 573 517 327 572 495 315

Temperature peaks (Temperature peaks (℃℃))


ResultsTemperature History (sensor) : Property 1

Measured

Calculated

1000rpm*100mm/min Optimized Condition

1000rpm*300mm/min Most AGG Condition

1500rpm*150mm/min Least AGG Condition



Measured

Calculated





Accumulated Effective Strain (Material)

Property 1

Property 2





Temperature History (Material)




Property 1

Property 2


Question for the Simulation

• Is that ok to use different materials properties for different welding conditions

• Why the accumulated effective strains are so different for different simulation properties? And which one is more accurate?

• For both properties, the temperature gaps for bottom and top region are very small


Unchanged OSU Results


Micro-Hardness Comparison

BottomTop

5083-H18 Before Heat-treatment

• Use data without Min&Max

70

80

90

100

0 0.5 1 1.5

Most AGG (300mm/min*1000rpm)Least AGG (150mm/min*1500rpm)Optimized (100mm/min*1000rpm)

Hv

Distance From Top Surface (mm)


5083-H18 After Heat-treatment

70

80

90

100

0 0.5 1 1.5

Most AGG (300mm/min*1000rpm)Least AGG (150mm/min*1500rpm)Optimized (100mm/min*1000rpm)

Hv

Distance From Top Surface (cm)

BottomTop



5083-O Before Heat-treatmentMicro-Hardness Comparison

70

80

90

100

-20 -15 -10 -5 0 5 10 15 20

Hv value - 100mm/min*1500rpmHv value - 300mm/min*1000rpm

Hv

Distance From Weld Centerline (mm)


AA5083 Micro-Hardness Comparison


Materials Received from Hitachi/GMI – Materials received for the current GM project


II – Materials received for the previous GM project•There is no detailed material description sheet/form I can find for these packages, so I just recorded as much information as I can find for each of them. They were received in or before 2005.


Thank you !


50g, 15s load

Indentation size: ~ 33*33um2

5083-H18 Before Heat-treatment


5083-H18 Optimized (100mm/min*1000rpm)Before Heat-treatment

BottomTop


70

80

90

100

0 0.5 1 1.5

Avg. of Tot.Avg. Without Min&Max

Hv

Distance From Top Surface


50g, 15s load



5083-H18 Most AGG (300mm/min*1000rpm)Before Heat-treatment

BottomTop


70

80

90

100

0 0.5 1 1.5



Hv


50g, 15s load



5083-H18 Least AGG (150mm/min*1500rpm)Before Heat-treatment

BottomTop


70

80

90

100

0 0.5 1 1.5



Hv


Sample Surface Blistering After Heat-treatment

Heat-treatment condition: 465 Co, 5 min

5083-H18 – No-Blistering

Optimized condition1000rpm * 100mm/min

Least AGG condition1500rpm * 150mm/min

Most AGG condition1000rpm, 300mm/min


5083-O – Blistering

1500rpm,100mm/min 1000rpm, 300mm/min Heat-treatment condition: 465 Co, 5 min

a

b

a

ba,b – Heat treated separately

under same condition.a is much worse than b.

a,b – Heat treated separatelyunder same condition.Both blistered badly.

BlisteringBlistering

Blistering Blistering


5083-O 1000rpm,300mm/minHeat-treatment condition: 465 Co, 5 min

a

b

c

d

Origins of AGG in FSW 5083 - Li Group...

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