Publikationsrepositorium - Helmholtz-Zentrum Dresden-Rossendorf

The dendrite growth kinetics and morphology have been of great interest in the solidification science and casting industry. A detailed analysis of the particular solidification phenomena (coarsening, fragmentation etc.) requires X-ray techniques with a better spatial and temporal resolution. High resolution experimental data are also very important for the verification of the existing microstructural models. In this work, in-situ synchrotron X-ray radiography and diffraction methods have been combined to study the evolution of dendritic microstructures during the solidification of Ga - In alloys. The directional solidification experiments were performed at the ID19 and BM20 beamlines (ESRF, France) at a high spatial resolution of < 1 µm. The study is especially focused on the sidearm evolution, retraction and detachment, dendrite morphology and orientation. The sidearm evolution is quantified by an image analysis in a manner appropriated for comparison to simulations. Furthermore, we report on the reconstruction of crystallographic orientation of growing dendrites by using the CaRIne crystallography software. Our measurements show that the Indium dendrites grow along the <110> orientation, typically observed in body-centered metals. Our future work will include the systematic study of the evolution of dendritic morphologies at finite cooling rates and under the impact of melt flow.