Effects of cell size on compression and bending strength of aluminum-foamed material by complex stirring in induction heating

This paper investigated the effects of various process parameters on the mechanical properties of aluminum-foamed material. For the sake of this, complex stirring, which combined electromagnetic stirring with mechanical stirring, was used to fabricate aluminum foam materials by varying fabrication conditions. Pore size and its volume fraction increased as temperature of molten metal increased. When stirring, pore generation increased and distribution state improved as the stirring velocity increased. Pore size and porosity fraction increased as the foaming velocity increased. It resulted in pore size and shape to be poor material properties. Pore size and porosity fraction increased as the foaming temperature increased. However, the inner flow by the expansion in the molten metal due to temperature gradient and gravitational liquid metal drainage into inter-pores would occur, which caused pores deformed. The compressive strength was inversely proportional to the cell sizes. The yield strength below 2 mm of cell size changed gradually, but the yield strength over 2 mm of cell size drastically decreased because the shape of cell changed from spheroidal to polyhedral structure.