Traditional solidification theory and technology research mainly revolve the casting process of ingots and castings. The cooling rate is usually within the range of 10–3–102 K/s. The cooling rate of large ingots is about l0−2 K/s, the cooling rate of medium castings is about 1 K/s, and the cooling rate of very thin castings during the die casting process may reach 102 K/s. Higher cooling rates require special rapid solidification techniques to achieve. Rapid solidification is defined as: the phase transition process from liquid to solid is very fast, thereby obtaining compositions, phase structures, and microstructures that cannot be obtained by ordinary castings and ingots.