Effects of Extrusion Methods and Powder Carriers on Powder Forming and Precursor Foaming Behavior in the Preparation Process of Aluminum Foam

摘要

Aluminum foam is a new type of material that can be used in many fields. Compaction conditions are the most important parameters that have influence on foam preparation process. So in this paper, detailed researches about extrusion methods and powder carriers are conducted. The results show that: compare with direct extrusion, pre-pressing can effectively eliminate the influences of hydrogen, obtain high density precursors. However, when the flank of the precursor is wrapped with copper, H2 can escape from the combination parts of Al and Cu, in early foaming stage. The minimum density is only 0.75g/cm~3, pore structures are almost round and nearly no plateau borders exist, so the quality of aluminum foam is still poor. When there is no copper wrapped, an oxide layer can be formed in the whole body of the precursor and limit the escaping of H2. The minimum density can reach 0.45g/cm~3, pore structures are polygonal with thin cell walls about 0.08mm. Thus high quality aluminum foams can be obtained by using pre-pressing and then extruding method and precursor sheet powder carrier.