Introduction and Background

Experiment Procedure

Joining of Al alloy and stainless

steel thin sheets by thermally

assisted plastic deformation

Chair for Hyper-functional Forming

Institute of Industrial Science, The University of Tokyo

Zhequn Huang and Jun Yanagimoto

Tensile Shear Test Optimal: W1.6-S1.7-T450-H22

Joining Mechanisms: Chemical bonding (800-nm-thick continuous interdiffusion layer at the interface, machoanchoring effect of the mechanical confinement and microanchoring effect.

Z: Supplied

thermal energy

Fracture

De-bonding

Distortion

Excessive

thinning

Crack

Sound joint

[0,0,0]

[0,0,-1]

[0,0,1]

Gap

Insufficient

stress

A6061P-T6

SUS304

1: excessive value 0: appropriate value -1: insufficient value

W1.6-S1.7-

RT

W1.6-S1.7-

T150-H22

W1.6-S1.7-

T300-H22

W1.6-S1.7-

T350-H22

W1.6-S1.7-

T400-H22

W1.6-S1.7-

T450-H22

W1.6-S1.8-

T300-H22

W1.6-S1.8-

T350-H22

Not bonded Not bonded Not bonded Bonded Bonded Bonded Bonded Bonded

A6061P-T6

SUS304S

Punch

DieW

Die

0.8 mm

1.2

mm

1.2

mm

(a) (b)

D =

1.7

4 m

m

1 mm1 mm

D =

1.7

3 m

m

1 mm

(d) W1.6-S1.7-T450-H28

D =

1.7

2 m

m

Distortion

1 mm

D =

1.7

2 m

m

La

= 0

.94 m

m

Lc

= 1

.03 m

m

Ld

= 1

.03 m

m

Lb

= 1

.00 m

m

A6061P-T6

SUS304

A6061P-T6

SUS304

A6061P-T6

SUS304

A6061P-T6

SUS304

(a) W1.6-S1.7-T350-H22

θa

(b) W1.6-S1.7-T400-H22

A6061P-T6

SUS304

1 mm

θb

(e) W1.4-S1.7-T400-H22

(c) W1.6-S1.7-T450-H22

Gap

A6061P-T6

θc

1 mm

(f) W1.2-S1.7-T400-H22

Gap

SUS304

Groove Width

W1.6: Groove width = 1.6 mm

r chamfer = 0.2 mm

W1.4: Groove width = 1.4 mm

r chamfer = 0.5 mm

W1.2: Groove width = 1.2 mm

r chamfer = 0.5 mm

Peel Test Optimal: W1.6-S1.7-T400-H22 with largest failure energy

Fuel consumption is linearly proportional to

the weight of transportation product.

Combining lightweight and non-lightweight materials

to develop lightweight hybrid structure is future trend.

Cross section

(a) Macroanchoring

1 μm

A6061P-T6

SUS304

1 μm

A6061P-T6

SUS304

(b) Microanchoring

Aluminum extruded sections

Aluminum sheet-sections

Aluminum casting-sections

Steel sheet-sections

Compression machine

assisted by induction heating

Experimental parameters

and used die with groove Parametric

optimization strategy

supplied plastic strain X, Y

supplied thermal energy ZDeterminants

3 m

SUS304

A6061P-T6

W1.6-S1.7-T400-H22

(neck region)(a) (b)

(c)

SUS304A6061P-T6

Macroanchoring

1 μm

A6061P-T6

SUS304

1 μm

A6061P-T6

SUS304

Microanchoring

W1.6-S1.7-T400-H22

(neck region)

~800 nm

interdiffusion layer

Aluminum alloy/steel hybrid components are widely used in different industrial areas.

However, further reducing component thickness for lightweight hybrid products has made

the dissimilar joining of Al alloy and steel thin sheets (less than 1 mm in thickness) a greater

challenge. In this research, an alternative dissimilar joining process by thermally assisted

plastic deformation is proposed for thin metallic sheets. The effects of various parameters

on the joining performance were investigated. After exposure to an elevated temperature of

450 ºC for 22 s, an optimized joint type was achieved by local plastic deformation using a

simple punch-die pair. This joint type exhibited an average joint efficiency factor of 85.2%

and average absorption energy of 1.69 kN∙mm in tensile shear tests, as well as satisfactory

joining performance in peel tests. Such high-quality dissimilar joints were realized by simply

operated die forging in air, without any yielding gas, flux brazing or surface treatment.

Source: Bandivadekar et al.

2008. Report No. LFEE 2008-

05 RP, MIT.

Source: European Aluminium

Association, 2013.

http://www.alueurope.eu.

The W1.6-S1.7-T450 joint shows

highest average ultimate tensile

shear load in tensile shear test. The

joint efficiency factor is 85.2%.

0.0

0.5

1.0

1.5

2.0

2.5

3.0

0.0 0.5 1.0 1.5 2.0 2.5

Te

ns

ile

sh

ea

r lo

ad

(k

N)

Displacement (mm)

W1.6-S1.7-T350-H22

W1.6-S1.7-T400-H22

W1.6-S1.7-T450-H22

W1.6-S1.7-T450-H28

(a)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

0.0 0.5 1.0 1.5 2.0 2.5

Te

ns

ile

sh

ea

r lo

ad

(k

N)

Displacement (mm)

W1.6-S1.7-T400-H22W1.4-S1.7-T400-H22W1.2-S1.7-T400-H22

(b)

0

50

100

150

200

250

300

350

400

450

0 5 10 15 20

Peel F

orc

e (

N)

Displacement (mm)

W1.6-S1.7-T350-H22

(a)

0

50

100

150

200

250

300

350

400

450

0 5 10 15 20

Peel F

orc

e (

N)

Displacement (mm)

W1.6-S1.7-T400-H22

(b)

0

50

100

150

200

250

300

350

400

450

0 5 10 15 20

Peel F

orc

e (

N)

Displacement (mm)

W1.6-S1.7-T450-H22

(c)

Punch

Die

Induction coil

Blank holderSpring

(0.8-mm-thick A6061P-T6)

Thermo couple(0.5-mm-thick SUS304)

(a)

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 Time (s)

Heating History CurveForming Stroke

Stroke (S)

Heat Holding Time (H)

Air Cooling

Heat Rate (15 ⁰C/s)

Temperature (⁰C)

Stroke (mm)

FormingTemperature (T)

(b)

Punch

Die

Induction coil

Blank holderSpring

(0.8-mm-thick A6061P-T6)

Thermo couple(0.5-mm-thick SUS304)

(a)

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 Time (s)

Heating History CurveForming Stroke

Stroke (S)

Heat Holding Time (H)

Air Cooling

Heat Rate (15 ⁰C/s)

Temperature (⁰C)

Stroke (mm)

FormingTemperature (T)

(b)