Fast scanning calorimetry of phase transitions in metals

Abstract

Quantitative analysis of phase transitions in metals under exceptional conditions is still a challenge. Thanks to the development of nanotechnology and microelectromechanical systems, fast scanning calorimetry (FSC) has been developed, providing an ideal instrument to study phase transitions under extremely nonequilibrium conditions. For one thing, the ultrafast scanning rate up to 106 K/s can simulate some realistic conditions, e.g., gas atomization, 3D printing, and laser forming, to monitor in situ the phase transition process and reveal its mechanism. For another, the ultrahigh sensitivity, less than 1 nJ/K, makes it possible to capture phase transitions in micro- and even nano-sized materials and therefore to study the size effect on phase transitions. In addition, more and more analytical methods such as X-ray diffraction (XRD) and transmission electron microscopy (TEM) are combined with FSC to realize structural characterization. In this chapter, we review applications of FSC in melting, solidification, and solid-state phase transition of metallic materials to demonstrate the unique phenomena revealed by this technique.