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

Abstract

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 (λ = 0.124 Å) 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 MoSS, Mo3Si, and Mo5SiB2, which can be directly observed during in situ experiments for the first time.