LAUSR

Abstract The morphology of solid metallic foams is governed by the evolution of the cellular structure during the foaming process in the liquid state. We study quantitatively film ruptures in liquid aluminium alloy foams and determine their temperature dependence and spatial distribution and analyse how they evolve during isothermal holding. The coalescence rate of AlSi8Mg4 and AlSi9 foams was found to increase linearly with temperature within the range studied. We introduce the term “internal structural stability” and quantify it by using the total number of bubbles and the coalescence rate. Furthermore, a probabilistic approach allows us to fit and extrapolate the number of bubbles as a function of holding time and to predict foam half-lives. Application of the two methods allows us to compare two established foamable alloys and to conclude that the internal structure of liquid AlSi8Mg4 foams is around 50% more stable than of AlSi9 foams.