Aluminum Foam Structures and Compressive Properties Produced from Multiple and Differently Arranged Precursors

Abstract Large closed cell aluminum foam components, produced through a powder metallurgical route, normally need multiple foamable precursors. The larger the size of components, the more precursors are required. The placement of precursors in the mold prior to sintering is important for a successful foaming. The present study shows that the initial precursor arrangement has a significant effect on the final foam structure and its mechanical properties. The largest foam expansion, close to the geometry of the mold, with more uniform pore distribution was found in the foam with the arrangement of four precursors, which were placed horizontally at the bottom of the mold in two layers. This was due to the delayed foam collapse as a result of the different onsets of individual precursor expansion. The difference in heat conduction of distinct precursor positions resulted in different cellular structural characteristics which strongly affect compressive behavior of the Al foams.