In situ X-ray microtomography study of the solidification and remelted microstructures of Al-Cu alloys

In situ 3D observations of the formation of dendritic microstructures and their evolution during solidification of Al-Cu alloys were carried out by using fast X-ray microtomography performed at the European Synchrotron Radiation Facility (ESRF), Grenoble. The technique allows obtaining in situ 3D images of the microstructure every minute. The influence of the cooling rates on the variation with time of the specific solid-liquid interface area was investigated. Furthermore local observations were also performed during solidification and during isothermal holding in order to identify the various ripening mechanisms that are occurring in dendritic structures.