2. In Situ Studies of the Solidification Dynamics of Metal Alloys

Since the 1990s, tens of 3^rd generation synchrotron X-ray facilities have been built around the world and made available for research in almost all scientific disciplines. The high brilliance, high coherence and tunable energy of synchrotron X-rays allow researchers in physical and biological science to probe many new dynamic processes in spatial and temporal resolution that are not possible before. This chapter firstly gives a brief review of the advances of X-ray science and the fundamental laws governing the interactions of X-rays with matter, and then focuses on a critical review and discussion of state of the art real-time and in situ studies of the solidification processes using synchrotron X-rays. The emphasis is on new scientific insights and discoveries in solidification science of metallic alloys, which are enabled by synchrotron X-rays based advanced real-time characterization techniques and the future challenges in this fast advancing research field. Although the knowledge, techniques, and practice described in Chap. 2 are generally in the context of solidification processes, they are applicable to many other materials syntheses and manufacturing processes. Readers are referred to the monographs or books published in the field of synchrotron science for broader topics, knowledge, and practice.