Abstract
In the powder metallurgical process to produce foamed cellular aluminum, relative densities and foamabilities of hot pressed or powder forged preforms have been investigated to find out more suitable consolidation techniques compared with hot extrusion for small-and medium-sized productions. Coarser aluminum powder suited to achieve highly expanded foams for the present processes. Regardless of the examined two consolidation processes, the preforms with relative density over 0.97 were able to expand into foams with 60 to 70% porosity. However, it was important to apply a fixed consolidation condition in.order to obtain foams with stable porosity. Both hot pressed preforms and powder forged ones showed basically the same foamabilities as those of hot extruded preforms, except for the fact that 20 K and 50 K higher foaming temperatures were suitable for the hot pressed preforms and the powder forged ones, respectively.
