Aluminium foam Powder Metallurgy - SAVAluminium foam Product information 2.2.01.08/06 GB Powder Metallurgy Powder Extrusion Technology · Slovak Academy of Sciences / Bratislava (Proto-

Aluminium foam

Product information 2.2.01.08/06 GB

Powder MetallurgyPowder Extrusion Technology

· Slovak Academy of Sciences / Bratislava (Proto-

typing, Process analysis, plant engineering and

construction)

· TU Vienna / Institute of Materials Science and

Testing / o. Univ. Prof. Dipl. Ing. Dr. techn.

H. Peter Degischer

· Neue Materialien Fürth GmbH / Prof. Dr. R. F.

Singer

· LKR - Ranshofen (on-road test)

· MIT - Boston (Computation, Simulation)

Permanent Cooperation with:

Field of ActivitiesAluminium foam

For the production of foamed aluminium, Al pow-

der is mixed with a product releasing gas at higher

temperature and then compacted. This foaming

agent is placed into a mold form and heated up

until the agent starts to foam. Immediately there-

after the mold is taken out of the furnace and

cooled off, so the aluminium foam part is frozen

in shape. The outcome of this process is a closed

cell aluminium foam showing a thin casting skin

on the surface.

Powder Metallurgy

This technology is creating benchmarks. During

this process, metal powders are being compacted

using extrusion technologies. This represents an

additional technology besides existing sinter

technologies, especially for components with

2-Dimensional outlines. Material properties can be

designed precisely for requirements. Structural

parts with high stiffness, thanks to the various

possibilities of combining Non-Ferrous powders

can be named as example.

Application of Aluminium foamThe combination of top attributes such as high

stiffness, low weight and high energy absorption

enables Aluminum foam to qualify for specific

requirements within the automotive, aviation,

railway and engine building industry. Aluminium

foam is also qualifying for other high potential

applications in the field of Architecture and Design,

where electromagnetic shielding, structural dam-

ping, flame resistance and a decorative surface

structure is required.

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The data in this application brochure correspond with the current status of our knowledge and experience. We do not assume any guaranty for the information given. We reserve theright to alter any product data as a result of technical progress or further developments in the manufacturing process.

Contact:

Alulight® International GmbH

Lach 22A-5282 RanshofenAustriaPhone: (+43) (7722) 64564-0Fax: (+43) (7722) 64564-610E-mail: [email protected]: www.alulight.com

Characteristics


· high stiffness at very low density

· Absorption of high impact energies, regardless

of the impact direction

· heat insulation

· highly efficient in sound absorption, electro-

magnetic shielding and vibration damping

· heat resistant and not inflammable

· fully recyclable

Summary of Results:

· the storage modulus of Alulight® does not

depend on resonant frequency – it can be consi-

dered as a static value of the modulus

· Alulight®’s modulus of elasticity depends strongly

on density. The dependence obeys the power

law function with an exponent of about 1.6

· the base alloy composition has no significant

influence on the modulus of elasticity of Alulight®

(tests with densities up to 1000 kg/m3).

Main Applications:

· stiff structural components with minimized

masses – especially beam and membrane-like

structures

· as a filling material for hollow structures Alulight®

helps to move resonant frequencies outside

operating frequency range

· heat resistant structures with high stiffness and

low density made at reasonable cost

· isotropic properties, non-combustibility, form

stability and simple recycling make it an alterna-

tive to wood (Alulight® floats on water)

· heat resistant, isotropic and stiff cores for sand-

wich structure

Material density p modulus E Elp2

[kg/m3] [GPa] [10-5 GPa.kg2/m6]

Alulight® 500 5 2,0

epoxy: 1300 3 0,3

steel: 7800 210 0,4

aluminium: 2700 69 1,0

glass: 2500 70 1,1

concrete: 2500 50 0,8

The structure modulus elasticity of foam cannot be determined as usual from the slope of the stress strain curve. This is due to plasticdeformations in the early stress stages. Elastic vibration loading is therefore the more appropriate method. Alulight® was testedas follows: The rod-shaped sample was vibrated longitudinally with an “impact-hammer”.Test sample: Alulight® rod-shaped specimens (diameter of 17 mm, min. length of 300 mm) with varying densities and base alloycompositions were used for the tests.

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Characteristics of Panels


One has the choice between pure aluminium foam

and additionally reinforced panels with densities

ranging from 0,4–0,6 kg/dm3. Expanded metal

may be embedded within the aluminium foam in

order to improve bending stiffness.

Alulight®-sandwiches can also be produced with

plain or shaped aluminium cover sheets either on

one or both sides, if higher bending strength or

specific surface quality is required.

Pre-cut panels with outlines after customer require-

ments are available on request.

Alulight®-panels can be nailed, screwed, bolted

joint, using connection elements built in the foamed

structure or mounted using variety of standard

tools for wall, ceiling and floor mounting.

Deflection of Alulight®-panels and sandwiches

in comparison with Al sheet of the same weight

(four point bending test under various loads).

Test: hx 450 x 50 mm

Alulight® panels are available with casting skin in

various dimensions. Our panels can be machined

as easily as wood, using conventional techniques

like sawing, drilling, turning, etc.

Care should be taken, as the very thin surface skin

can be removed by machining, thus revealing the

inner pore structure.

Material AlSi AlMgSi0,6 AlMgSi0,6+T6

E-modulus: GPa 5 5 5

min. plastic collapse stress: MPa 7 7 12

min. bending stiffness: MPa 8 8 15

bending stiffness: % 210 210 210(Al-sheet, same weight)

heat conductivity at 20°C: W/m.K 6–15 6–15 6–15

electrical conductivity: 108 S/m 3 3 3

energy absorption: MJ/m3 4,5 4,5 9(20 MPa compressive stress)

loss factor: 0,003 0,003 0,003

Def

lect

ion

[m

m]

50 N

100 N

150 N

Deflection of Alulight®-panels and sandwiches:

9

8

7

6

5

4

3

2

1

0Alulight-sandwichone side h-13mm

Alulight-panelh-10mm

Alulight-panelh-8mm

Alulight-sandwichdouble sided h-10mm

Al-sheeth-3mm

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Density: 500–550 kg/m3.

Data were based on a closed geometry 50x50mm with a wall thickness by 7mm.

Energy Absorption

Product information 2.2.01.08/06 D

Impact absorbers protect passengers and fragiledevices from the effects of sudden impact. This isachieved by converting the impact energy intoplastic deformation energy, keeping the peak forceacting on the protected object below the levelwhich could cause damage. The material must alsoprovide a long deformation path to sufficientlyreduce the deceleration of the protected object.

The energy absorption properties can be adjustedthrough foam density respectively pore size andmay be optimized through further heat treatment.

Because of those excellent absorption propertiesAlulight® aluminium foams are already used asserial part for crash absorption by leading automo-tive manufactures.

Main Applications:

· deformable car body parts for protection of

passengers form crash (also side protection)

· safety pads for lifting and conveying systems

· protective covers for high speed rotating

machines

Summary of Results:

· Alulight®´s cell walls start to buckle (wrought

alloys) and fracture (cast alloys) at low stresses

allowing for extensive compression with an ade-

quate deceleration path

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100

90

80

70

60

50

40

30

20

10

0 10 20 30 40 50 60 70 80Deformation (%)

Load

(kN

)

100

90

80

70

60

50

40

30

20

10

0 10 20 30 40 50 60 70 80

Effic

ency

of

abso

rbtio

n (%

)

Deformation (%)

Example of compressive load- deformation and absorption efficiency- deformation curves of Alulight® for comparision between bulk Aluminium profile and aluminium foam as crash absorbers.

Al–profile: 1,75 kg/m

Al–foam: 1,3 kg/m

Co

mp

ress

ion

str

ess

(MPa

)

Deformation (%)

Both curves describe the minimum and maximum possibleenergy absorption of Alulight® depending on densityalloy and heat treatment.

Trial Samples:AlMgSi aluminium foamdensity 0,22 g/ccmØd= 25mml = 30mm

AlMgSi aluminium foamdensity 0,70 g/ccml x b x h = 47 x 55 x 35 mmHeat treated

Test MethodUniaxal compression testCompression speed: 3mm min

AlSi–foam–density 0,22 g/ccm

AlMgSi–foam–density 0,70 g/ccm-HT

Measuring of impact energy absorption:

40

35

30

25

20

15

10

5

00 10 20 30 40 50 60 70 80

Energy absorption by comparision

Measuring conditions: Al-foam: 55x55mm; 1,35kg/mAl-profil: 60x90x2,5mm; 1,75kg/m

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Contact:


Lach 22A-5282 RanshofenAustriaPhone: (+43) (7722) 64564-0Fax: (+43) (7722) 64564-610e-mail: [email protected]: www.alulight.com


The data in this application brochure correspond with the current status of our knowledge and experience. We do not assume any guaranty for the information given.We reserve the right to alter any product data as a result of technical progress or further developments in the manufacturing process.

Design and architecture:

A process of design and modelling which also takes

into consideration the aesthetic aspects. Intuitive

creation of buildings and objects to raise emotions

through individual beauty.

With Alulight® a new, ageless material is available

to transfer theory and philosophy of sensual per-

ception into practice.

Due to the moulding capabilities of Alulight® there

is also the possibility to produce 3 dimensional

shapes.

Application potentials:

· furniture

· lay construction

· adornment for desks or chairs

· cladding constructions

· ceilling plates

· signboards with embossed text, letters or com-pany logos.

· fire protection / defence applications

Aesthetic with Attributes:

· 4 to 5 times lighter than bulk aluminium,stiffer than solid aluminium at the same weight

· each surface is individual

· flame resistante

· 100% recyclable

· good magnetic fields and electromagnetic wavesshielding efficiency

· lower thermal conductivity than solid aluminium

If required aluminium foam can be finished, coated

or also gummed. If a particular smooth surface is

desired the aluminium foam has to be primed

before lacquering to clear the roughness

of the textile like casting skin.

We are pleased to assist you by searching for special

lacquers, coatings or surface treatments.


Main Applications:

· structural material for various cases gear boxes

or covers which suffer from mechanical vibrations

· damping material to fill hollow parts or profiles

Summary of Results:

· The loss factor of Alulight® is significant higher

than the loss factor of Aluminium

· The damping ability of aluminium foam allows

to reduce the noice iduced by vibrations

· damping ability of Alulight® depends insignifi-

cantly on resonant frequency

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Resonance Decrease:

Structural damping is the effect of internal friction

within changing a material vibration energy into

heat. This reduces excessive noise and vibration by

converting them into heat to be expelled into the

surrounding area.

Vibration energy in cellular structures is dissipated

by the slight plastic deformation of the thin walls

separating the pores. It can also be reduced by

friction between the surfaces of cracks appearing

in the pore walls.

Damping factor (decay) of 25 mm Alulight® foampanel, 5 mm Al-sheet and 3 mm Al-sheet.

Trial samples:Al-foam: 500x500x25mm; 2kgAl-panel: 500x500x3mm; 1,9kgAl-panel: 500x500x5mm; 3,3kg

Test methodThe samples were exited in longitudinal vibration bythe „impact hammer“ method. The amplitude decaywas measured with an acceleration sensor and afrequency analyzer.

dec

ay-d

amp

ing

fac

tor

Eta

(-)

frequency f (Hz)

1,4E-02

1,2E-02

8,0E-03

6,0E-03

4,0E-03

2,0E-03

0,0E+00

500 1000 1500 2000 2500

Time vs. surface acceleration dependance, ability todamp vibration after impact by impact hammer

3mm Al-panel: 1,9 kg

Al-foam 25mm: 2,0 kg

5mm Al-panel: 3,3 kg

Damping factor

Vibration behavior

Acc

eler

atio

n (m

s-2)

Acc

eler

atio

n (m

s-2)

Acc

eler

atio

n (m

s-2)

Time (ms)

Time (ms) Time (ms)

Electromagnetic shielding


Electromagnetic waves can cause malfunctions in

various electronic devices. Negative influence on

human health is also being investigated. Electro-

magnetic wave shielding should be used to protect

electronic devices and rooms interiors from elec-

tromagnetic waves.

The material for this purpose should possess good

electric conductivity to minimize the penetration

of waves into the material and low magnetic per-

meability to convert magnetic energy into heat.

Main Applications:

· cover boxes for electronic devices

· wall and ceiling plates for protection of rooms

against entering or releasing of electromagenetic

waves within the frequency range of 0,1 to

1000 MHz

Preliminary Results:

· Alulight® possesses very good magnetic field

shielding effectiveness.

· electric shielding effectiveness of Alulight® is

comparable with the one of silicon steel for

frequencies up to 10 MHz. Alulight® is superior

for higher frequencies.

· electromagnetic shield effectiveness of Alulight®

depends significantly on the frequency

Shie

ld e

ffec

tive

nes

s [d

B]

Frequency [MHz]

Electric field shielding effectiveness as a function

of frequency for samples of same weight.

Si-steel

Electric field shielding effectiveness:

140

120

100

80

60

40

20

00,1 1 10 100 1000

Alulight®

Test method:

Electric and magnetic shielding tests by KEC

method.

Trial sample:

Alulight®-sheets (140 x 140 x 8,5 mm) with the

density of 510 kg/m3 were used as specimens.

Silicon steel sheet (140 x 140 x 0,5 mm) and

bulk aluminium sheet(140 x 140 x 10 mm) were

used as reference materials.

Shie

ld e

ffec

tive

nes

s [d

B]

Frequency [MHz]Magnetic field shielding effectiveness as a function of frequency forsamples of same weight.

massive Al

Si-steel

Magnetic field shielding effectiveness:

140

120

100

80

60

40

20

00,1 1 10 100 1000

Alulight®

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Conductivitythermal / electric


Only a small portion of Alulight®´s cross section is

conductive. These are the pore walls with the

conductivity value of the base alloy. The pore walls

are continiously covered with non-conductive alu-

mina. The main part of the cross section is formed

by the pores filled with air which is non-conductive.

Alulight® is therefore far less conductive than bulk

aluminium.

Main Applications:

· recyclable heat shields

· boxes for electronic devices, where also electro-

magnetic shielding or crash energy absorption

are important

Summary of Results / Electrical Conductivity:

· electric conductivity decreases with density of

Alulight®

· electric conductivity of Alulight® is a non-linear

Summary of Results / Thermal Conductivity:

· Thermal conductivity of Alulight® is only 1/10 of

that of base aluminium

The electric conductivity of Alulight® as a function of density (electricconductivity of massive Aluminium is 37/106 S/m-1)

Test method:

The electric conductivity was calculated from

the geometry and the resistance of the sample.

The resistance measurement was performed by

the four point method.

Trial sample:

Cylindrical specimens of Alulight® with various

densities were used ( Ø 17 mm, length 300 mm)

elec

tric

co

nd

uct

ivit

y [1

0-1

S/m

]

density [kg/m3]

Measuring of electric conductivity:

50

40

30

20

10

0

0,0 0,5 1,0 1,5 2,0 2,5 3,0

Test method:

Comparative method for different temperatures

up to 400°C.

Trial sample:

Cylindrical specimens of Alulight® with different

densities prepared from various Al-alloys were

used. The outer surface of the samples (Ø 25

mm, length 20 mm) was removed by electric

discharge machining.

Thermal conductivity of Alulight® as a function of density and base alloy

Ther

mal

co

nd

uct

ivit

y [W

/mK

]

Measuring of thermal conductivity:

250

200

150

100

50

0430 500 2700

Al

AlSi12

AlMgSi

density [kg/m3]

function of density and obeys the power-law de-

pendence with an exponent of 1.5

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Documents

Aluminium foam Powder Metallurgy - SAVAluminium foam Product information 2.2.01.08/06 GB Powder Metallurgy Powder Extrusion Technology · Slovak Academy of Sciences / Bratislava (Proto-