Synchrotron radiation micro-CT with phase contrast for high-temperature in-situ microstructural characterization of Al-Sn composite phase change materials

Thanks to immiscibility of Al and Sn, Al-Sn binary alloys can act as composite Phase Change Materials. These materials can store and release latent heat reversibly exploiting the solid-liquid transition of Sn at about 230 degrees C, combining this function with the thermal stability and the high conductivity of Al. To understand phenomena occurring during thermal cycles at high temperature, micro-CT analysis with phase contrast imaging was applied in-situ to Al-Sn alloys produced with different powder metallurgy processes. Tests were carried out at the European Synchrotron Radiation Facility (ESRF) in Grenoble, France. Qualitative and quantitative analysis on 3D reconstructions were conducted in Matlab environment. With respect to previous studies, in-situ analysis pro-vided a deeper understanding of the microstructural development depending on powder metallurgy processes on the composite microstructure. The overall form stability of the systems during a thermal cycle was proved. Molten Sn leakage phenomena are limited and related to Sn-rich areas directly connected to surface.