Powder Metallurgy Powder Extrusion Technology. Aluminium foam. Field of Activities. Application of Aluminium foam. Permanent Cooperation with:

Transcription

1 /6 GB Aluminium foam Powder Metallurgy Powder Extrusion Technology Field of Activities Aluminium foam For the production of foamed aluminium, Al powder 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 thereafter 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. Application of Aluminium foam The 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 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. applications in the field of Architecture and Design, where electromagnetic shielding, structural damping, flame resistance and a decorative surface structure is required. Permanent Cooperation with: Slovak Academy of Sciences / Bratislava (Prototyping, 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)

2 /6 GB Characteristics high stiffness at very low density Absorption of high impact energies, regardless of the impact direction heat insulation highly efficient in sound absorption, electromagnetic shielding and vibration damping heat resistant and not inflammable fully recyclable Material density p modulus E Elp 2 [kg/m 3 ] [GPa] [1-5 GPa.kg 2 /m 6 ] Alulight 5 5 2, epoxy: 13 3,3 steel: 78 21,4 aluminium: , glass: ,1 concrete: 25 5,8 The structure modulus elasticity of foam cannot be determined as usual from the slope of the stress strain curve. This is due to plastic deformations in the early stress stages. Elastic vibration loading is therefore the more appropriate method. Alulight was tested as 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 3 mm) with varying densities and base alloy compositions were used for the tests. Summary of Results: the storage modulus of Alulight does not depend on resonant frequency it can be considered 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 1 kg/m 3 ). 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 alternative to wood (Alulight floats on water) heat resistant, isotropic and stiff cores for sandwich structure

3 /4 GB Characteristics of Panels One has the choice between pure aluminium foam and additionally reinforced panels with densities ranging from,4,6 kg/dm 3. Expanded metal may be embedded within the aluminium foam in order to improve bending stiffness. 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. 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 requirements 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 [mm] Deflection of Alulight -panels and sandwiches: N 1 N 15 N Alulight-panel h-8mm Alulight-panel h-1mm Alulight-sandwich one side h-13mm Alulight-sandwich double sided h-1mm Al-sheet h-3mm Deflection of Alulight -panels and sandwiches in comparison with Al sheet of the same weight (four point bending test under various loads). Test: hx 45 x 5 mm Material AlSi AlMgSi,6 AlMgSi,6+T6 E-modulus: GPa min. plastic collapse stress: MPa min. bending stiffness: MPa bending stiffness: % (Al-sheet, same weight) heat conductivity at 2 C: W/m.K electrical conductivity: 1 8 S/m energy absorption: MJ/m 3 4,5 4,5 9 (2 MPa compressive stress) loss factor:,3,3,3 Density: 5 55 kg/m3. Data were based on a closed geometry 5x5mm with a wall thickness by 7mm.

4 /6 D Energy Absorption Impact absorbers protect passengers and fragile devices from the effects of sudden impact. This is achieved by converting the impact energy into plastic deformation energy, keeping the peak force acting on the protected object below the level which could cause damage. The material must also provide a long deformation path to sufficiently reduce the deceleration of the protected object. The energy absorption properties can be adjusted through foam density respectively pore size and may be optimized through further heat treatment. Because of those excellent absorption properties Alulight aluminium foams are already used as serial part for crash absorption by leading automotive manufactures. Compression stress (MPa) Measuring of impact energy absorption: 4 AlSi foam density,22 g/ccm 35 AlMgSi foam density,7 g/ccm-ht Both curves describe the minimum and maximum possible energy absorption of Alulight depending on density alloy and heat treatment. Trial Samples: AlMgSi aluminium foam density,22 g/ccm Ød= 25mm l = 3mm AlMgSi aluminium foam density,7 g/ccm l x b x h = 47 x 55 x 35 mm Heat treated Deformation (%) Test Method Uniaxal compression test Compression speed: 3mm min Load (kn) Energy absorption by comparision 1 Al profile: 1,75 kg/m 9 8 Al foam: 1,3 kg/m Efficency of absorbtion (%) Deformation (%) 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 adequate deceleration path 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. Measuring conditions: Al-foam: 55x55mm; 1,35kg/m Al-profil: 6x9x2,5mm; 1,75kg/m 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

5 /4 GB 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 perception into practice. Due to the moulding capabilities of Alulight there is also the possibility to produce 3 dimensional shapes. 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. 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 1% recyclable good magnetic fields and electromagnetic waves shielding efficiency lower thermal conductivity than solid aluminium Application potentials: furniture lay construction adornment for desks or chairs cladding constructions ceilling plates signboards with embossed text, letters or company logos. fire protection / defence applications office@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 Printed in the Fed. Rep. of Germany 2.6/3.DD ECKA Granulate GmbH & Co. KG TD5/8

6 /6 GB 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. decay-damping factor Eta (-) Damping factor 1,4E-2 1,2E-2 8,E-3 6,E-3 4,E-3 2,E-3,E frequency f (Hz) Damping factor (decay) of 25 mm Alulight foam panel, 5 mm Al-sheet and 3 mm Al-sheet. Trial samples: Al-foam: 5x5x25mm; 2kg Al-panel: 5x5x3mm; 1,9kg Al-panel: 5x5x5mm; 3,3kg Test method The samples were exited in longitudinal vibration by the impact hammer method. The amplitude decay was measured with an acceleration sensor and a frequency analyzer. Vibration behavior Acceleration (ms-2) Acceleration (ms-2) Acceleration (ms-2) Time (ms) Time vs. surface acceleration dependance, ability to damp vibration after impact by impact hammer 3mm Al-panel: Al-foam 25mm: 5mm Al-panel: Time (ms) 1,9 kg 2, kg 3,3 kg Time (ms) 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 insignificantly on resonant frequency structural material for various cases gear boxes or covers which suffer from mechanical vibrations damping material to fill hollow parts or profiles

7 /6 GB Electromagnetic shielding Electromagnetic waves can cause malfunctions in various electronic devices. Negative influence on human health is also being investigated. Electromagnetic wave shielding should be used to protect electronic devices and rooms interiors from electromagnetic waves. The material for this purpose should possess good electric conductivity to minimize the penetration of waves into the material and low magnetic permeability to convert magnetic energy into heat. Shield effectiveness [db] Magnetic field shielding effectiveness: Alulight Magnetic field shielding effectiveness as a function of frequency for samples of same weight. Si-steel massive Al, Frequency [MHz] Test method: Electric and magnetic shielding tests by KEC method. Trial sample: Alulight -sheets (14 x 14 x 8,5 mm) with the density of 51 kg/m 3 were used as specimens. Silicon steel sheet (14 x 14 x,5 mm) and bulk aluminium sheet(14 x 14 x 1 mm) were used as reference materials. Shield effectiveness [db] Electric field shielding effectiveness: Alulight Si-steel 4 2, Frequency [MHz] Electric field shielding effectiveness as a function of frequency for samples of same weight. 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 1 MHz. Alulight is superior for higher frequencies. electromagnetic shield effectiveness of Alulight depends significantly on the frequency 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,1 to 1 MHz

8 /6 GB Conductivity thermal / 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 alumina. 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. electric conductivity [1-1 S/m] Measuring of electric conductivity: ,,5 1, 1,5 2, 2,5 3, The electric conductivity of Alulight as a function of density (electric conductivity of massive Aluminium is 37/16 S/m -1 ) density [kg/m 3 ] 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 3 mm) Summary of Results / Electrical Conductivity: electric conductivity decreases with density of Alulight electric conductivity of Alulight is a non-linear function of density and obeys the power-law dependence with an exponent of 1.5 Thermal conductivity [W/mK] Measuring of thermal conductivity: 25 Al 2 AlSi12 AlMgSi Thermal conductivity of Alulight as a function of density and base alloy density [kg/m 3 ] Test method: Comparative method for different temperatures up to 4 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 2 mm) was removed by electric discharge machining. Summary of Results / Thermal Conductivity: Thermal conductivity of Alulight is only 1/1 of that of base aluminium recyclable heat shields boxes for electronic devices, where also electromagnetic shielding or crash energy absorption are important