Process Parameters and Foaming Agents Used in Manufacturing of Aluminium Metallic Foams:A Review

Porous metals and metallic foams are composite materials in which one phase is gaseous and another phase is solid metal. The mechanical behavior of these materials depends mainly on the mechanical properties of the solid metallic phase, the structural configuration of the solid and the density of the composite ρc, relative to the density of the solid phase ρs. The primary distinction between a porous metal and metallic foam is the relative density, metal gas composites with a relative density (ρc/ρs) above 0.3 are generally considered porous materials, while those with a relative density below 0.3 are generally considered to be metallic foams or honey combs. Another distinction between the two is in the interaction between adjacent voids in the structure. Porous metals and metallic foams can have open cells, with completely interconnected voids, or closed cells, with each void being isolated by a solid film. This review outlines the process parameters and foaming agents used in manufacturing methods of Aluminium metallic foams and discusses benefits and concerns associated with their uses. Many research works have been done on this particular topic and various technologies have been proposed and applied at experimental and field levels.