The effect of temperature and cascade collision on thermal conductivity of 3C-SiC: A molecular dynamics study

Abstract

The cubic silicon carbide 3C-SiC, the significant nuclear material used to manufacture the nuclear fuel in High Temperature Gas-cooled Reactor (HTGR), operates under a high temperature and neutron flux condition. The effect of temperature and irradiation on thermal conductivity of 3C-SiC were investigated with the molecular dynamics method. The equilibrium and non-equilibrium methods were utilized to calculate the thermal conductivity of 3C-SiC and the results of tersoff/zbl and MEAM interatomic potential were compared. Exponential decay of thermal conductivity with increasing temperature was illustrated. The irradiation effect was simulated with a high-energy Si atom and subsequent cascade collision, a multiple-phase simulation procedure was employed and the number of four kinds of point defects was counted. Finally, a relatively smaller simulation cell was used to analyze the impact of the incident atom with various velocities on the thermal conductivity of 3C-SiC. The computed results showed the cascade collision, caused by a higher-energy atom, would induce the lower thermal conductivity of 3C-SiC.