PNNL

Abstract

Damage accumulation simulated previously has been used to study volume swelling of 3C-SiC, and to calculate the elastic constants, bulk and elastic moduli of the cascade-amorphized SiC. The swelling increases rapidly with dose at low-dose levels, but the rate of increase decreases dramatically at higher dose with a saturation volume change of 8.2% for the cascade-amorphized state. The elastic constants in the cascade-amorphized SiC decrease about 22% for C11 and C12, 43% for C44, and 23% for bulk and elastic moduli. In order to understand defect annealing of damage accumulation, the stable Frenkel pairs created at low energy events have been annealed at different temperatures, using MD methods, to determine the time required for interstitials to recombine with vacancies. The results show that the low activation energies qualitatively overlap with experimental values observed during low temperature recovery. Thus, the present results suggest that low temperature recovery processes are associated with the spontaneous recovery of Frenkel pairs.