Foamability of particle reinforced aluminum melt

The foaming of aluminum melt of LKR-Austria is investigated. The foaming was performed in a furnace chamber at adiabatic conditions to keep the foam in liquid state. The foams were taken out from the chamber after 1, 10 and 100 min isothermal holding time and cooled in air or quenched in water. The final cellular structure depends on the following parameters: particle (composition, shape and size, volume fraction), gas (composition and purity), the particle-surface interactions, matrix alloy composition and temperature of foaming. Metallographical examinations are carried Out after freezing the foamed melt by the help of Scanning Electron Microscopy. The cell wall thickness, the particle distribution and the existing phases are determined. Transmission Electron Microscopy and Auger Electron Spectroscopy are used to analyze the surface skin of the cells and to determine the oxide layer thickness depending on the different foaming gases. An equipment called High Temperature Maximum Bubble Pressure Tensiometer (HTMBPT) was built to measure the apparent surface tension of the particle-stabilized melt. Semi quantitative description of the experimental phenomena are presented.