Multiscale Discrete Crystal Growth in the Solidification of 20SiMnMo5 Steel

Abstract

The solidified microstructures of metal alloys are produced by the process of crystal growth. However, some processes of crystal growth may remain uncovered because the solidification of metal alloys usually happens at high temperature with tiny growth scale and high growth speed. In the current work, based on the solidified microstructures, the crystal growth process of 20SiMnMo5 steel is investigated by abductive reasoning. The discrete crystal growth is identified at different scales. In the sub-microstructure scale, the basic elements of microstructures, such as single cellular grain, single dendritic arm, and single lamellar, are produced by the growth and convergence of discrete crystals. In the microstructure scale, the cellular microstructures, the lamellar microstructures, and dendritic microstructures are produced by discrete crystal growth. And the characteristic parameters of discrete crystal growth in this scale decide some characteristic parameters of solidified microstructures. The discrete crystal growth also happens in the mesoscale, which accounts for the formation of a channel zone. Besides, the faceted interface is observed in the crystal growth of 20SiMnMo5 steel.