Manufacturing and investigation of aluminium matrix bimodal metal foams

Abstract

Metal matrix foams (MMFs) are mostly used in the automotive industry due to their high specific energy absorbing capacity and relatively low weight. During this research, bimodal metal matrix foams were produced, where the filler was ceramic hollow spheres (CHSs) made of high-purity alumina with the nominal diameters of Ød1 = 7 mm and Ød2 = 2.4 mm. The hollow spheres of different sizes were used in 1:1, 2:1 and 4:1 volume ratio, which after mixing can be considered as uniformly distributed. Al99.5 was infiltrated between the CHSs with low pressure to create a cellular material. The manufacturing parameters have a significant influence on the properties of the finished metal matrix foam. Different preheating temperatures, melt temperatures, infiltrating pressures and time was applied to achieve proper wetting and filling. Samples were evaluated based on macro images and microscopic photographs.

Manufacturing and Comparison of Sr Modified or Unmodified AlSi12 Eutectic Alloy Matrix Unimodal and Bimodal Composite Metal Foams

“…The exact method was discussed in previous publications. [20,40] For the casting, a steel frame was used to bear the applied pressure on the chamber. The CHSs were poured into a bottom-perforated mild steel (S235) closed section, supported underneath with an alumina (Al 2 O 3 ) quilt layer, to prevent flow-through of the low-viscosity melt.…”