Document Type : Research Article


Innovative Metals Research Unit, Department of Metallurgical Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok, 10330, Thailand


Interconnected open-cell Al foams, with various fractions of recycled Al alloy scrap, have been produced using a sintering and dissolution process (SDP). The foams are suitable for various functional applications, such as heat exchangers, bone-replacement implants, interconnects, catalyst supports, and sound insulators. Firstly, the NaCl paste was pelletised, by hand, to make spherical balls of approximately 5 mm diameter. The Al alloy scrap was obtained from turning operation in lathe machine.  Porous structure was obtained after dissolution of the NaCl balls. The microstructure of Al foams was examined using SEM and EDX.  The results show that pores were uniformly distributed along Al matrix and interconnected with surrounding pores. The compressive strength of the foams with small scrap content of 20 wt.% is increased. However, when scrap content is higher, the strength is decreased, as a result of incomplete thermal bonding between Al powder and scrap particle, and excessive oxide content in foam microstructure.

Graphical Abstract

Manufacture of Functional Open-cell Al Foams with Recycled Al Scraps using NaCl Ball Space Holder