Evolution of Defects and Defect Clusters in β-SiC Irradiated at High Temperature

A molecular dynamics study has been performed to investigate the generation and evolution of damage states in irradiated β-SiC at high temperature. It is found that most of the C antisites (Si_C) are created during the early collisional phase, while the Si antisites (C_Si) are significantly produced during the thermal spike phase. A modified near-neighbor point defect density (NPDD) is introduced to study the spatial aggregation of different defects during the displacement cascades, and feature of defect clusters evolution is analyzed in details. The dominated types of vacancy clusters after the displacement cascades are two- and three-size chainlike ones. And the vacancy NPDD (V-NPDD) decreases as the recoil energy increases. Furthermore, after the thermal spike phase, there is an additional annealing process during which the interstitials and antisites turn into defect clusters, respectively.