[PPT] - Interface structural analysis of similar and dissimilar magnetic PowerPoint Presentation

SLIDE 1

R. Raoelison, M. Rachik, N. Buiron
R. Raoelison, M. Rachik, N. Buiron
R. Raoelison, M. Rachik, N. Buiron
R. Raoelison, M. Rachik, N. Buiron

Interface structural analysis of similar and dissimilar magnetic pulse welded joints

Laboratoire Roberval, Université de Technologie de Compiègne UTC, France

Workshop Impulse forming & joining Workshop Impulse forming & joining Workshop Impulse forming & joining Workshop Impulse forming & joining IBS Belgium, 7 IBS Belgium, 7 IBS Belgium, 7 IBS Belgium, 7-

8 may 2013

8 may 2013 8 may 2013 8 may 2013 Project MSIM (2010-2012): Funded by Région Picardie

SLIDE 2

MOTIVATION MOTIVATION MOTIVATION MOTIVATION

Development of multi-material assembly for lightweight structures → MPW : joining solution Optimization of the MPW → improvement of durability and reliability of dissimilar-material assemblies

Current challenge Current challenge Current challenge Current challenge : Project MSIM Project MSIM Project MSIM Project MSIM :

Driving the MPW toward its optimal ability for an efficient welding of dissimilar-material assemblies

Analysis of the interaction process parameters/joint quality
Analysis of the effect of metal dissymetry on the joint quality
Modeling and computational simulation of the MPW
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Interface structural analysis of similar and dissimilar magnetic pulse welded joints

present results : weld quality depending on the present results : weld quality depending on the present results : weld quality depending on the present results : weld quality depending on the process parameters process parameters process parameters process parameters

Modeling and computational simulation of the MPW
Feasibility study and development of tooling

Experimental approach : Experimental approach : Experimental approach : Experimental approach :

characterization and classification of the different joints encountered
relation between weld quality and process parameters
weldability study of Al/Al and Al/Cu assemblies

SLIDE 3

Material and method Material and method Material and method Material and method

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Comparison between two cases of assembly

Comparison between two cases of assembly Comparison between two cases of assembly Comparison between two cases of assembly :

Similar materials : Al6060T6/Al6060T6 Dissimilar materials : Al6060T6/Cu Material chemical composition (% weight) Material properties Welding test investigated with identical parameter sets σ (Ωm)-1 Tf(°C) ρ(kg/m3) E(GPa) G(GPa) Rm(MPa) Rp (MPa) Ar(%) Hv Mg Si Fe Mn Cr Zn Ti Cu Al Al6060T6 0,8-1,2 0,4-0,8 0,7 0,15 0,04-0,35 0,25 0,15 0,15-0,4 Balance Cu

99,9
Geometrical characteristic of the samples

d D L Flyer : D=25mm d=22mm L= 50mm Target : d

2

d1 l1 l2 d1 l1= 21mm d2 l2= 23mm σél(Ωm)-1 Tf(°C) ρ(kg/m3) E(GPa) G(GPa) Rm(MPa) Rp0,2(MPa) Ar(%) Hv Al6060T6 2,5.107 650 2,7.103 70 26,6 290 240 10 80 Cu 5,8.107 1065 8,9.103 124 46,6 250 200 14 80

SLIDE 4

→ dimensional characterization dimensional characterization dimensional characterization dimensional characterization

Characterization of the joint Characterization of the joint Characterization of the joint Characterization of the joint

Peel test Torsion-shear test Stress Stress Stress Stress Stress Stress Stress Stress Weld Weld Weld Weld weld weld weld weld

→ deviation

f the failure

→ failure at the interface

weld

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Inner tube

Flyer Weld Compression

Microstructure examination → structural characterization structural characterization structural characterization structural characterization

16mm

→ mechanical characterization mechanical characterization mechanical characterization mechanical characterization Push-out test Interface structural analysis of similar and dissimilar magnetic pulse welded joints

SLIDE 5

Joint characteristics Joint characteristics Joint characteristics Joint characteristics

Dimensional characterization Dimensional characterization Dimensional characterization Dimensional characterization

Unwelded interface Beginning of bonding (trace of residue) Beginning of good welding (thin weld) Large weld Striation : circular path due to interfacial deformation → ductile and potentially permanent weld

Structural characterization Structural characterization Structural characterization Structural characterization

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Structural characterization

Structural characterization Structural characterization Structural characterization

Beginning of bonding Beginning of good welding Potentially permanent weld

Interface SubGB Emergence of slip band

EBSD analysis Interface structural analysis of similar and dissimilar magnetic pulse welded joints

SLIDE 6

→ grain deformation (strong)

EBSD analysis EBSD analysis EBSD analysis EBSD analysis TEM analysis TEM analysis TEM analysis TEM analysis

Interface Sub grain Slip band

Interface features Interface features Interface features Interface features TEM analysis TEM analysis TEM analysis TEM analysis

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Multiscale characterization of the Al/Al joint

Multiscale characterization of the Al/Al joint Multiscale characterization of the Al/Al joint Multiscale characterization of the Al/Al joint

TEM analysis of the interface :

high density of dislocation
grain size (< 500nm) → modification of the mecanichal properties

Nanoidentation → gradient of hardness (Hv interface ≈1.5*Hv base metal) Interface structural analysis of similar and dissimilar magnetic pulse welded joints

SLIDE 7

Further SEM analysis Further SEM analysis Further SEM analysis Further SEM analysis

creation of cavities (heterogeneous material structure ) : decohesion at the phases interface
création of cavities from inclusion : matrice/inclusion decohesion (e.g. due to precipitates)

Al6060T6 material : with Al Al6060T6 material : with Al Al6060T6 material : with Al Al6060T6 material : with Alx

x x x-

Mg

Mg Mg Mgy

y y y-

Si

Si Si Siz

z z z precipitates

precipitates precipitates precipitates

Formation of the dimple :

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Fractal analysis of the Al/Al joint

Fractal analysis of the Al/Al joint Fractal analysis of the Al/Al joint Fractal analysis of the Al/Al joint

observation of spheroïdal inclusion inside ome dimples -

EDX analysis of the inclusion : diffraction of Al and Mg → development of dimple: potentialydue to precipitates

Interface structural analysis of similar and dissimilar magnetic pulse welded joints

SLIDE 8

MET analysis of the Al/Al joint MET analysis of the Al/Al joint MET analysis of the Al/Al joint MET analysis of the Al/Al joint

Base metal : → matrix of Al → needle shape precipitate Interface : → needle shape p/tes dissapear → spheric p/tes appear

Structural analysis of the precipitates Structural analysis of the precipitates Structural analysis of the precipitates Structural analysis of the precipitates

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→ spheric p/tes appear

SLIDE 9

Fractal analysis Fractal analysis Fractal analysis Fractal analysis

→ creation of macro-cavities (crack initiation sites)

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Analysis of defective Al/Al joint

Analysis of defective Al/Al joint Analysis of defective Al/Al joint Analysis of defective Al/Al joint

→ regular distribution of humps → porous zone within the hump

Interface structural analysis of similar and dissimilar magnetic pulse welded joints

SLIDE 10

SEM examination of the porous pockets and mechanichal effect SEM examination of the porous pockets and mechanichal effect SEM examination of the porous pockets and mechanichal effect SEM examination of the porous pockets and mechanichal effect

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Local analysis of the porous zones

Local analysis of the porous zones Local analysis of the porous zones Local analysis of the porous zones → porosity with high density (attributable to cavitation) porosity with high density (attributable to cavitation) porosity with high density (attributable to cavitation) porosity with high density (attributable to cavitation)

5 10 15 20 0,5 1 1,5 2 2,5 Ucolumn(mm) F(kN)

Large weld Thin weld Weld with voids

Effect on the mechanical behaviour Effect on the mechanical behaviour Effect on the mechanical behaviour Effect on the mechanical behaviour

SLIDE 11

Effect of material dissymetry Effect of material dissymetry Effect of material dissymetry Effect of material dissymetry : effect on the weld features effect on the weld features effect on the weld features effect on the weld features

Al/Al Al/Al Al/Al Al/Al → Formation of intermetallic phase

U=6.5kV,g=1.5mm U=6.5kV,g=1.5mm U=6.5kV,g=1.5mm U=6.5kV,g=1.5mm U=6.5kV,g=1.5mm U=6.5kV,g=1.5mm U=6.5kV,g=1.5mm U=6.5kV,g=1.5mm

Al/Cu Al/Cu Al/Cu Al/Cu

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→ continuous layer or discontinous pockets

Interface structural analysis of similar and dissimilar magnetic pulse welded joints

SLIDE 12

EDS and TEM analysis

Diffraction in the Al part Diffraction in AlnCum → ordered structured → crystal lattice

Structural analysis of the intermetalic phase Structural analysis of the intermetalic phase Structural analysis of the intermetalic phase Structural analysis of the intermetalic phase

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Intermetalic

Intermetalic Intermetalic Intermetalic :

→ complex structure → random distribution → extremely fine grains

amorphous phase

amorphous phase amorphous phase amorphous phase

formation by hyperquenching

formation by hyperquenching formation by hyperquenching formation by hyperquenching (quick cooling : 104-106K/s ) Interface structural analysis of similar and dissimilar magnetic pulse welded joints

SLIDE 13

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Further characterization of the intermetallic phase

Further characterization of the intermetallic phase Further characterization of the intermetallic phase Further characterization of the intermetallic phase

5 10 15 20 1 2 3 Ucolumn (mm) F (kN)

Al/Al thin weld Al/Cu thin weld

brittle fracture of the interface

→ porous structure (size of ~ hundreds nm) → fracture surface : rupture by fragmentation

Mechanical behaviour Mechanical behaviour Mechanical behaviour Mechanical behaviour Amorphe phase : britle weld Amorphe phase : britle weld Amorphe phase : britle weld Amorphe phase : britle weld

SLIDE 14

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Further mechanical

Further mechanical Further mechanical Further mechanical characterization characterization characterization characterization of the

f the
f the
f the intermetallic

intermetallic intermetallic intermetallic phase phase phase phase

Intermetallic Intermetallic Intermetallic Intermetallic layer layer layer layer

50 100 150 200 250 300 0.00 0.50 1.00 1.50 2.00 2.50 3.00 F (mN) penetration (µ µ µ µm) Intermetallic Base Metal

Intermetallic Intermetallic Intermetallic Intermetallic → no plastic deformation surrounding the indent, increase of the hardness no plastic deformation surrounding the indent, increase of the hardness no plastic deformation surrounding the indent, increase of the hardness no plastic deformation surrounding the indent, increase of the hardness

Force / displacement indentation curve Force / displacement indentation curve Force / displacement indentation curve Force / displacement indentation curve

Base Metal Base Metal Base Metal Base Metal plastic plastic plastic plastic deformation deformation deformation deformation

Hv int/lic = 1.9 GPa, Hv BM=1,5 GPa Hv int/lic = 1.9 GPa, Hv BM=1,5 GPa Hv int/lic = 1.9 GPa, Hv BM=1,5 GPa Hv int/lic = 1.9 GPa, Hv BM=1,5 GPa E int/lic = 77 GPa, E BM= 63 GPA E int/lic = 77 GPa, E BM= 63 GPA E int/lic = 77 GPa, E BM= 63 GPA E int/lic = 77 GPa, E BM= 63 GPA

SLIDE 15

1 2 3 4 5

U(kV)

g(mm)

perennial weld (2mm<ww<7mm)

ring-shaped weld (1.5mm<ww<2mm)

○ bad weld

Brittle weld

Effect of metal dissymetry Effect of metal dissymetry Effect of metal dissymetry Effect of metal dissymetry

Al/Al Al/Al Al/Al Al/Al Welding range Welding range Welding range Welding range Comparison of Comparison of Comparison of Comparison of achieved good weld achieved good weld achieved good weld achieved good weld

Large residue Large residue Large residue Large residue

Al/Al Al/Al Al/Al Al/Al Al/Cu Al/Cu Al/Cu Al/Cu

Short length residue Short length residue Short length residue Short length residue

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1

2 3 4 5 6 7 8 9 1 2 3 4 5 1 2 3 4 5 6 7 8 9

U(kV)

g(mm)

thin weld (ws~2mm)

ring-shaped weld (0.1mm<Ws<2mm)

○ bad weld

Brittle weld Brittle weld

Al/Cu Al/Cu Al/Cu Al/Cu reduction Illustration of Al/Cu weld above Illustration of Al/Cu weld above Illustration of Al/Cu weld above Illustration of Al/Cu weld above the upper limit (brittle weld) the upper limit (brittle weld) the upper limit (brittle weld) the upper limit (brittle weld)

(case with U=7.5kV, g=4mm)

Interface structural analysis of similar and dissimilar magnetic pulse welded joints

SLIDE 16

Conclusions Conclusions Conclusions Conclusions

interface structural analysis of a similar AA6060T6 weld :
weld enable to undergo plastic deformation
potentialy permenant weld: ductile with a wavy interface
welded interface with high density of dislocations and nanograin
heat effected interface : disappearance of needle shape precipitate and

formation of new sheroidal ones

formation of defective weld with voids and porous zone
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→ combination of Al6060T6/Cu : not good for the interface integrity

reduction of the weldability range

formation of CuaAlb intermetallic phase
intermetallic : → discontinous pocket or continous layer

→ amorphous phase and/or with nanograin → phase with nanovoids → brittle and low resistant weld

interface structural analysis of a dissimilar AA6060T6/Cu weld :

Interface structural analysis of similar and dissimilar magnetic pulse welded joints

SLIDE 17

1. RAOELISON R., BUIRON N., RACHIK M., HAYE D., FRANZ G., HABAK M., ‘Study of the

elaboration of a practical weldability window in magnetic pulse welding’, Journal of Materials Processing Technology (2013) http://dx.doi.org/10.1016/j.jmatprotec.2013.03.004.

2. RAOELISON R., BUIRON N., RACHIK M., HAYE D., FRANZ G., ‘Efficient welding

conditions in magnetic pulse welding process’, Journal of Manufacturing Process, 14(2012), 372-377.

3. RAOELISON R., BUIRON N., RACHIK M, ‘Investigation of material dissymetry effect on

magnetic pulse welding of Al/Cu assembly: effect of intermetallic on the weld characteristic and the weldability’, (to be submitted).

Related papers

and the weldability’, (to be submitted).

4. RAOELISON R., BUIRON N., RACHIK M., HAYE D., FRANZ G., ‘Assessment of Gap and

Charging Voltage Influence on Mechanical Behaviour of Joints Obtained by Magnetic Pulse Welding’, Proceedings of the 4th International Conference of High Speed Forming, Germany 2012, 207-216.

5. RAOELISON R., BUIRON N., RACHIK M., HAYE D., HABAK M., ‘Elastoplastic and Damage

Behaviour of Magnetic Pulse Weld Interfaces’, Proceedings of the 10th International Conference on Technology of Plasticity, Aachen, Germany, p. 1160-1163, 2011