Ultrafast X-Ray Phase Contrast Imaging of a Gasless Reactive System Using Third Generation Synchrotron Radiation

We report an ultrafast x-ray phase-contrast imaging study of a gasless composite reactive system undergoing high heating rates (10$^{4}$ -- 2.5 x 10$^{5}$ K/s). Construction of an imaging system utilizing a high-speed CMOS camera (Vision Research Phantom v7.3) and the third-generation synchrotron at the Advanced Photon Source at Argonne National Laboratory allows for imaging of microstructural changes of the reactive system over previously unstudied time and length scales. Using Computer-Assisted Electrothermography (CAE), the heating rate of the gasless reactive system Mo-Si is controlled and its kinetics are measured. A physical description of the changes undergone by the system during melting and reaction are captured by the high-speed imaging system and correlated to the recorded CAE data. These changes include microscale nucleated melting and the formation of fluid instabilities.