Dynamics of interface pattern formation in 3D alloy solidification: first results from experiments in the DECLIC directional solidification insert on the International Space Station

One of the critical microstructures in directional solidification of alloys is the cellular/dendritic pattern that governs the properties and reliability of the solidified material. Our quantitative understanding of the solid-liquid interface pattern has come mainly from experiments in thin samples where the microstructure selection is shown to occur during the dynamical growth process. A more realistic configuration is to examine the evolution of microstructure in three-dimensions, which is not possible terrestrially since convection effects dominate in bulk samples and prevent precise characterization of microstructure dynamics. Recently, experiments under low gravity conditions have been carried out jointly by NASA and CNES in the model transparent system succinonitrile-camphor on board the International Space Station using the Directional Solidification Insert in the DECLIC facility. After a brief description of the experimental setup and methods, the first results on dynamics of interface pattern formation obtained in microgravity will be presented and the information extracted from their quantitative analysis will be discussed.