172 Integrally molded foam parts

Illichmann GmbH give examples of the ways in which MEPURA ALULIGHT® can be molded to give complex shapes which have dense skins with foamed cores - 'syntactic' metal structures* (see Chapter 2, Section 2.4). Figure 17.3 shows examples of skinned structures which are both stiff and light. The thickness of the outer skin can be enlarged by a special casting technique, creating three-dimensional sandwiches with isotropic core properties. The small amount of metal (<40%) reduces the thermal conductivity significantly, but the electrical conductivity remains high. The structure has good damage tolerance and energy-absorbing capability.

The moldings are made from various aluminum alloys, primarily (1) commercially pure aluminum; (2) heat-treatable aluminum alloys of the 6000-series and (3) aluminum alloys based on AlSi12 casting alloy. Mechanical properties can be optimized by appropriate heat treatment of the base alloy. Surface treatment is also possible using standard techniques for aluminum and its alloys.

* Contact details: Illichmann GmbH Grossalmstrasse 5, A-4813, Altmunster, Austria. Phone: (+43) 761288055-0; fax (+43) 761288055-29.

Mepura Metallpulvergesellschaft m.b.H., Ranshofen, A-4813 Altmunster Grossalmstrasse, 5, Austria. Phone: (+43) 761288055-0; Fax (+43) 772268154.

Dr Frantesek Simancik, Institute of Materials and Machine Mechanics, Slovak Academy of Sciences, Racianska 75, PO Box 95, 830 08 Bratislava 38, Slovak Republic. Phone: (+42) 7254751; fax (+42) 7253301.

Figure 17.3 Foamed aluminum components with integral skins. (Courtesy of Mepura Metallpulvergesellschaft m.b.H)

MEPURA and Illichmann suggest applications for ALULIGHT moldings which include

• Lightweight machine castings with improved sound and vibration damping

• Impact energy absorption components for cars, lifting and conveyor systems

• Stiff machine parts with significantly reduced weight

• Housings for electronic devices providing electromagnet and thermal shielding

• Permanent cores for castings, replacing sand cores

• Isotropic cores for sandwich panels and shells

• Fillings in hollow shapes to inhibit buckling

• Heat shields and encapsultors

• Floating structures at elevated temperatures and pressures

• Sound absorbers for difficult conditions

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