MICROSTRUCTURAL EVOLUTION OFSiCDURING MELTING PROCESS

Microstructural evolution of SiC during melting process is simulated with Tersoff potential by using molecular dynamics. Microstructural characteristics are analyzed by radial distribution function, angle distribution function and Voronoi polyhedron index. The results show that the melting point of SiC with Tersoff potential is 3249 K. Tersoff potential can exactly describe the changes of bond length, bond angle and Voronoi clusters during the process of melting. Before melting, the length of the C – C bond, Si – Si bond and Si – C bond is 3.2, 3.2 and 1.9 Å, respectively. The bond angle distributes near the tetrahedral bond angle 109°, and the Voronoi clusters are all (4 0 0 0) tetrahedron structures. After melting, the C – C bond and Si – Si bond are reduced, while the Si – C bond is almost unchanged. The range of bond angle distribution is wider than before, and most of the (4 0 0 0) structures turn into three-fold coordinated structures, (2 3 0 0), (0 6 0 0) and (2 2 2 0) structures. The simulation results clearly present the microstructural evolution properties of SiC during the melting process.