15-02-2010, 12:50 PM
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INTRODUCTION
Metal foam is a dispersion of gas bubbles in a metallic bulk material
These are extremely lightweight materials
It contains 50% or more holes
They have some very promising properties
Structure o f metal foam
In metal foams cells are divided into distinct cells. the boundaries of these materials are made of solid material, the interior are voids.
Light weight Al foam
The best quality metal foams presently available
It has a density of from 300 to 1,000 kg/m³, that is, 30 to 100% that of water. Components made of the material can therefore be expected to float.
Characteristics of Al foam
are very stiff at a very low weight
are very effective in terms of acoustical absorption
are very effective in terms of electromagnetic shielding and structural damping
absorb impact energy regardless of impact direction
are much more stable than organical materials like wood or plastics
are decorative are completely recyclables and hence do not cause any harm to our environment
Advantages
Metal foams provide excellent energy absorption features at a higher strength level as compared to foamed polymers
Metal foams are easily processed by sawing, drilling, milling, etc,
Metal Foams can be joined by adhesive bonding, brazing, and TIG and laser welding techniques.
It does not erode, even under the effects of air flow or vibration.
It is easily recyclable.
Provides sound absorption at low frequencies at a smaller material thickness in comparison with other absorption materials such as glass or mineral wool fibers or polymer foams.
Conclusion
There is considerable interest in the applications of metallic foams from a wide range of industries.
Impact and energy absorption are key
applications, particularly within the
transport industries.
Thermal management properties can
be exploited by the electronics industry
in particular.
Cost is still a major factor.