Fabrication of Aluminium Foam Components by Using Powder Compact Melting Method

Recently, closed cell cellular metals have been gaining a very high interest due to their unique characteristic applications in various technology domains. They combine the advantages of a metal with the structural advantages of foam. Among these, aluminium foams have created a great interest due to their light weight structure and their various applications in the automotive, aerospace and allied industries. Aluminium foam possesses high stiffness and low density, it has good energy-absorbing properties making it good for crash-protection and packaging and it has attractive heat-transfer properties that permit to use these materials to cool electronic equipment and as heat exchangers in engines. However, its manufacturing techniques and characterization methods need more attention. The inadequate knowledge on the physical phenomena governing the foaming process does not allow to obtain products with repeatable characteristics. In this paper aluminium foams in various fabrication components were produced by applying the powder compact melting method. In particular metal powders (AlSi7) and powdered gas-releasing blowing agents (TiH₂) were mixed and subsequently pressed to obtain a foamable precursor material. The resulting precursor was then foamed by heating it up to above its melting point. Experimental tests were performed to study the fabrication of aluminum foam components and with the extent of optimize the pressing parameters of the foamable precursor material, the foaming temperature and the heating rate during foaming. It was studied the effects of geometrical discontinuities in the mould (such as holes, restrictions, etc) on the evolution and on the morphology of metal foams.