Microstructural evolution and crystalline behavior in silicon carbide nano-powder during selective laser melting: A molecular dynamics simulation

Abstract

Silicon carbide (SiC), with its isotropic three-dimensional diamond lattice structure, emerges as a promising candidate for SiC device production through selective laser melting (SLM). The appeal lies in its simplified fabrication process, coupled with outstanding thermal properties, high hardness, and remarkable wear resistance. This potential of SiC in SLM not only streamlines the fabrication process but also harnesses the exceptional properties inherent in SiC. In this study, we utilized molecular dynamics (MD) simulations to model the SLM process. A nanopowder bed made up of approximately half a million atoms of SiC was simulated as a two-layer quasi-2D system. Controlled heating of SiC meltpools, slightly surpassing the melting temperature, facilitated the monitored coalescence of nano-powders, resulting in successful melting and the formation of continuous domains within the meltpools. The observed reduction in crystalline structures is due to the elevated thermal energy imparted to the SiC atoms during the heating process, which disrupts the atomic arrangement and leads to a transition from crystalline to amorphous states. The subsequent solidification process, characterized by a high cooling rate, led to the establishment of final amorphous solidified domains. Looking ahead, our research aims to delve into exploring the structural and functional characteristics of the produced SiC devices, evaluating their potential applications across diverse technological domains.