Kinetics of coalescence in liquid aluminium foams
The cell wall rupture kinetics for a collection of AlSi9 foam samples kept at a constant temperature over the melting point for a long time period (700 s) has been characterized by in situ X-ray radioscopy. The images obtained have been computed by using image analysis algorithms allowing the identification of the cell wall ruptures in the molten state. The time evolution, the spatial distribution and the number of cell wall rupture events are studied in this work. The cell wall rupture rate was determined for the first time in liquid aluminium foams. Part of the results obtained has been explained in terms of the spatial distribution of temperature obtained by different heating configurations and measured by thermographic techniques. The progressive coarsening and density redistribution of the cellular structure and the drainage due to gravity have been also considered. The local temperature seems to be critical for the rupture phenomena and the temperature distribution clearly affects the foam density distribution.