Optimization of cellular structure of aluminum foams produced by powder metallurgy method

This paper describes a new method for optimizing the cellular structure of AlMg4Si8 alloy foams manufactured via powder metallurgy. The cellular structure was improved by pretreating TiH2 with a layer of Sn powder, which was then remixed with an AlMg4Si8 alloy used as the raw material for the preparation of the precursor. TiH2 was completely encapsulated in the molten Sn at an early stage of foaming when the matrix alloy was still solid, so that liberated H2 was fully captured when TiH2 began to decompose. The interpore flow of H2 along the cracks in the solid matrix was avoided, improving the utilization ratio of TiH2 as a blowing agent. After determining that 4.0 wt% Sn cladding was capable of almost completely encapsulating 0.5 wt% TiH2, the final cellular structure was optimized and regular circular pores were obtained.