Room Temperature Superplastic Deformation of Closed-Cell Zinc Alloy Foams

Lightweight aluminum foams are attractive energy absorbing material for automotive machines. Strength of aluminum foams manufactured through casting process is not so much high as dense aluminum alloys due to difficult alloying. Ductility of aluminum foams manufactured through powder metallurgical process is low due to fine oxide dispersions. In this paper, we introduce new metallic foam having excellent energy absorbing property. Closed-cell Zn-22 mass%Al eutectoid alloy foams are manufactured through powder metallurgical process. The Zn-22Al alloy is known as typical superplastic material and shows superplastic deformation below 523 K, even at room temperature. Using titanium hydride powder as a foaming agent, the porosity as high as 60% is achieved. Solution treatment followed by quenching causes ductile compressive deformation at room temperature. In addition, the absorbed energy of the Zn-22Al foams are much larger than those of conventional aluminum foams.