SYNTHESIS OF ALUMINIUM FOAMS BY THE POWDER METALLURGY PROCESS: COMPACTING OF PRECURSORS

Aluminium foams, produced by the powder-metallurgy route, have a good potential for use in weight-sensitive structural parts. The goal of this study was to evaluate the properties and to optimize the preparation of precursors by a powder-compacting process. Various compacting pressures, from 200 MPa to 900 MPa, were used in the double-axial powder-compacting process for two different aluminium powders: pure aluminium and an AlSi12 alloy with the addition of 1 % of TiH2 as a foaming agent. The green density of the precursors and the distribution of the foaming agent were examined. The powder particles was also characterised. The results of the effective preparation of precursors are shown as the effectiveness of the foaming of the precursors. The relation between the powder characteristics, the aluminium-alloy properties and the preparation of precursors was studied by SEM/EDS analysis, powder-metallurgy standard testing of metallic powders, granulometry, etc. Different parameters were used for the precursor preparation and foaming. The foaming temperature varied between 680 degrees C and 770 degrees C, and the foaming time was from 6 min to 13 min. The relation between the properties and the applied production parameters was studied in detail and is described in this paper.