In situ Observation of Ternary Eutectic Growth in a Directionally Solidified Mo‐Si‐B Alloy using High‐Energy Synchrotron X‐Rays

Herein, synchrotron-generated high-energy X-ray is used to study growth behavior at the liquid-solid transition of multicomponent alloys during in situ directional solidification experiments at Deutsche Elektronen-Synchrotron (DESY), Hamburg, Germany. The unique "FlexiDS" sample environment is used to directly investigate crystal growth of a ternary eutectic Mo-17.5Si-8B alloy. During the directional solidification process, high-energy X-rays with a photon energy of 100 keV (lambda = 0.124 angstrom) are used in transmission to obtain Debye-Scherrer diffraction rings. The diffraction rings were obtained within the liquid phase, the liquid-solid interphase and the solidified eutectic crystals by scanning through the respective observation volume of interest. The results provide strong evidences for a coupled ternary eutectic growth of the phases Mo-SS, Mo3Si, and Mo5SiB2, which can be directly observed during in situ experiments for the first time.